c0t0d0s0.org - Technology http://www.c0t0d0s0.org/ the sun in a lighthungry universe en Serendipity 1.6 - http://www.s9y.org/ Deep insight into the behaviour of the SPARC T4 processor http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/vzLYNnTjEJE/7456-Deep-insight-into-the-behaviour-of-the-SPARC-T4-processor.html English Sun/Oracle Technology http://www.c0t0d0s0.org/archives/7456-Deep-insight-into-the-behaviour-of-the-SPARC-T4-processor.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=7456 0 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=7456 nospam@example.com (Joerg Moellenkamp) How the SPARC T4 Processor Optimizes Throughput Capacity: A Case Study. In this article the authors compare and explain the behaviour of the the UltraSPARC T4 and T2+ processor in order to highlight some of the strengths of the SPARC T-series processors in general and the T4 in particular. ]]> Sat, 07 Apr 2012 15:24:07 +0200 http://www.c0t0d0s0.org/archives/7456-guid.html http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/7456-Deep-insight-into-the-behaviour-of-the-SPARC-T4-processor.html BSD on a DUINOMITE http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/4cHX_27MbWM/7454-BSD-on-a-DUINOMITE.html English Technology http://www.c0t0d0s0.org/archives/7454-BSD-on-a-DUINOMITE.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=7454 0 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=7454 nospam@example.com (Joerg Moellenkamp) "UNIX ON PIC32 – MEET RETROBSD FOR DUINOMITE". The Duinomite is a small board based on a PIC32 microcontroller.
Serge did amazing job by porting the old days 2.11BSD Unix used to run on PDP-11 to PIC32 (MIPS). In just 128KB RAM footprint he manage to boot UNIX OS and you have 96KB left for applications.
]]> Wed, 04 Apr 2012 13:57:31 +0200 http://www.c0t0d0s0.org/archives/7454-guid.html http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/7454-BSD-on-a-DUINOMITE.html Deduping your redundancies http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/LjgMkUxFJrw/7358-Deduping-your-redundancies.html English Technology http://www.c0t0d0s0.org/archives/7358-Deduping-your-redundancies.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=7358 1 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=7358 nospam@example.com (Joerg Moellenkamp) pointed to an interesting article about about deduplication and it's impact to the resiliency of your data against data corruption on ACM Queue.

The problem in short: A considerable number of filesystems store important metadata at multiple locations. For example the ZFS rootblock is copied to three locations. Other filesystems have similar provisions to protect their metadata. However you can easily proof, that the rootblock pointer in the uberblock of ZFS for example is pointing to blocks with absolutely equal content in all three locatition (with zdb -uu and zdb -r). It has to be that way, because they are protected by the same checksum. A number of devices offer block level dedup, either as an option or as part of their inner workings. However when you store three identical blocks on them and the devices does block level dedup internally, the device may just deduplicated your redundant metadata to a block stored just once that is stored on the non-voilatile storage. When this block is corrupted, you have essentially three corrupted copies. Three hit with one bullet.

This is indeed an interesting problem: A device doing deduplication doesn't know if a block is important or just a datablock. This is the reason why I like deduplication like it's done in ZFS. It's an integrated part and so important parts don't get deduplicated away. A disk accessed by a block level interface doesn't know anything about the importance of a block. A metadata block is nothing different to it's inner mechanism than a normal data block because there is no way to tell that this is important and that those redundancies aren't allowed to fall prey to some clever deduplication mechanism.

Robin talks about this in regard of the Sandforce disk controllers who use a kind of dedup to reduce some of the nasty effects of writing data to flash, but the problem is much broader. However this is relevant whenever you are using a device with block level deduplication. It's just the point that you have to activate it for most implementation by command, whereas certain devices do this by default or by design and you don't know about it. However I'm not perfectly sure about that … given that storage administration and server administration are often different groups with different business objectives I would ask your storage guys if they have activated dedup without telling somebody elase on their boxes in order to speak less often with the storage sales rep.

The problem is even more interesting with ZFS. You may use ditto blocks to protect important data to store multiple copies of data in the pool to increase redundancy, even when your pool just consists out of one disk or just a striped set of disk. However when your device is doing dedup internally it may remove your redundancy before it hits the nonvolatile storage. You've won nothing. Just spend your disk quota on the the LUNs in the SAN and you make your disk admin happy because of the good dedup ratio ;-) However you can just fall in this specific "deduped ditto block"trap when your pool just consists out of a single device, because ZFS writes ditto blocks on different disks, when there is more than just one disk. Yet another reason why you should spend some extra-thought when putting your zpool on a single LUN, especially when the LUN is sliced and dices out of a large heap of storage devices by a storage controller.

However I have one problem with the articles and their specific mention of ZFS: You can just hit by this problem when you are using the deduplicating device for the pool. However in the specifically mentioned case of SSD this isn't the usecase. Most implementations of SSD in conjunction with ZFS are hybrid storage pools and so rotating rust disk is used as pool and SSD are used as L2ARC/sZIL. And there it simply doesn't matter: When you really have to resort to the sZIL (your system went down, it doesn't matter of one block or several blocks are corrupt, you have to fail back to the last known good transaction group the device. On the other side, when a block in L2ARC is corrupt, you simply read it from the pool and in HSP implementations this is the already mentioned rust.

In conjunction with ZFS this is more interesting when using a storage array, that is capable to do dedup and where you use LUNs for your pool. However as mentioned before, on those devices it's a user made decision to do so, and so it's less probable that you deduplicating your redundancies.

Other filesystems lacking acapability similar to hybrid storage pools are more "haunted" by this problem of SSD using dedup-like mechanisms internally, because those filesystem really store the data on the the SSD instead of using it just as accelerating devices.

However at the end Robin is correct: It's jet another point why protecting your data by creating redundancies by dispersing it several disks (by mirror or parity RAIDs) is really important. No dedup mechanism inside a device can dedup away your redundancy when you write it to a totally different and indepenent device. ]]> Wed, 29 Jun 2011 09:01:20 +0200 http://www.c0t0d0s0.org/archives/7358-guid.html http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/7358-Deduping-your-redundancies.html Synchronicity in asynchronicity http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/snM0BJ8evv4/7147-Synchronicity-in-asynchronicity.html English Solaris Technology http://www.c0t0d0s0.org/archives/7147-Synchronicity-in-asynchronicity.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=7147 5 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=7147 nospam@example.com (Joerg Moellenkamp)
As you know there are two important concepts of executing writes. Synchronous and asynchronous or to say it differently blocking or non-blocking. When you trigger an asynchronous write, the write call comes back, right after you issued the call. An synchronous write call (by definition) is only allowed to come back, when the system has assured (as far it's technically possible) that the data is on some kind of nonvolatile storage.

Synchronous writes are absolutely essential for example for mail servers: The MTA can't send OK to the MUA or to another MTA the "OK, got the mail", as long it's sure the mail is nonvolatile on the other server, because the sending MTA deletes it from its queue after such a OK. A mail could be lost, when the power fails after the OK, but before the non-volatile storing of the mail. So you send the OK afterwards. How to you ensure, that the OK is after the nonvolatile storing? Yes ... it's done by a sync write.

It's the same for databases: One of the important foundations of ACID is the synchronous write. Without synchronous writes, forget about the D ...

However a synchronous write has a problem and it is because of its greatest advantage. It doesn't come back until the write has been completed. The problem is that you can't do anything else in this time in this thread.

Translating this to an example in the real world, you can imagine this like being the dispatcher of large group of employees. When you give your employees their tasks synchronously, you give your employees the job and wait for the completion before you dispatch another job. You can be sure, that the task has been completed before you throw the the piece of paper with the todo, however it's not really efficient.

Switching back to asynchronous writes isn't an option as well, as the only way to check, if the write call was really processed through the complete code path and the code paths inside the HBA and the controller adjacent to the disk, is to read the location (okay, they are other reasons to do so, however that a completely different discussion). The asynchronous write call gives you no feedback of that the write call has been completed in terms of writing stuff to nonvolatile storage. Basically you trust the operating system that it will do everything right and aside of this there is absolutely no guarantee that asynchronously written data is on disk after a system crash.

Translated to the real world example, this would be like giving a task to an employee, throwing away the piece of paper where you wrote down the task ... and forget about it. Obviously you can work very fast this way, and often this works well, however when an employee quits or is absent due to illness, the job may not completed.

By the way: It's the same for reads. A reads blocks the calling process until the data has been delivered, and this time there is no way around with it with normal means. Reading is synchronous by necessity. The process can't say "Well ... when i have to wait for it ... i will take some other data available"

So, waiting processes until the write comes call returns, missing guarantees and no feedback on the other side. And reads synchronous anyway. And even more devastating: When a write or read call blocks a thread, because it waits until all the stuff between the OS and the disk has been done, no matter how many parallel disks or filesystem you have. How do you get out of this challenge?

There is a way around that and this is Asynchronous I/O. The read and writes are still synchronous or asynchronous in the sense of blocking or non-blocking. So you can have basically an synchronous write in a asynchronous I/O model. This is important: As a colleague said it years ago: You can configure Oracle to use a asynchronous I/O model, but you can't tell Oracle to use non-synchronous write semantics. Remember the D.

To use this model, there are a number of new calls in the OS that support this asynchronous I/O modell.

The write call aiowrite or read call call aioread returns right after you issue the call. Sounds like asynchronous write semantics. However there is an important difference: At first the read or write is now run in a concurrent thread and the aioread or aiowrite returns immediately after they are issued. But contrary to the asynchronous write semantic, you get a feedback about the result of the write.

There are essentially two important ways to yield this information, at first you could call the aiowait function. This returns as soon as a outstanding read or write triggered by aiowrite or aioread returns. It waits either forever (until an outstanding aio request completes), not at all ("Is something completed available ... no ... okay ... let's go further". You use this mode of operating to implement a polling mechanism) or wait for a certain time.

The other way is to implement a signal handler. Whenever a I/O request made by those calls, they will send the signal SIGPOLL, the signal handler can then dequeue the notification of a completed I/O request with aiowait (in fact, they have to because it's the only way to get those notifications out of the queue)

However: Both mechanisms notify (SIGPOLL fires, aiowait returns), when one of outstanding asynchronous requests is completed. They doesn't report the I/O call that has been completed. You have to find which one. Most often this is done by scanning the return code buffers of the aiowrite/aioread requests after you have initialized them with a value expressing "in progress". When a i/o request has been completed, it's set to something else, so you just have to scan for return code buffers, that are not on the state "in progress).

Translated into the real world, it's like dispatching a steady stream of tasks to your employees. However you don't monitor their progress yourself, but you have some colleagues for that. Those colleagues just send you a notification "Task xyz has been completed with that result" and could throw the piece of paper with the task away, as soon as this notification was send to you. You could do it at a jour-fixe, you could wait in front of your colleagues or you could wait for 5 minutes for completion notifications and then do something else for the next hours.

The advantage of asynchronous I/O is obvious: The application can issue I/O requests without waiting for the completion of others, you can even issue asynchronous reads. By doing so a single application thread can have multiple I/O requests in flight. However you addition you get still a feedback, that the I/O request has been successfully completed and you can use it in areas where you would have opted to use synchronous aka blocking write semantics in the past. Important to know: Your application must be enabled by the developers to use an asynchronous I/O pattern.

]]> Thu, 03 Feb 2011 08:21:00 +0100 http://www.c0t0d0s0.org/archives/7147-guid.html http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/7147-Synchronicity-in-asynchronicity.html Apple start to make public contributions to OpenJDK http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/HUduwfWsoJI/7133-Apple-start-to-make-public-contributions-to-OpenJDK.html Apple English Sun/Oracle Technology The IT Business http://www.c0t0d0s0.org/archives/7133-Apple-start-to-make-public-contributions-to-OpenJDK.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=7133 1 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=7133 nospam@example.com (Joerg Moellenkamp) I'm very happy to let you know that today we made the first public contribution of code to the OpenJDK project for Mac OS X. This initial contribution builds on the hard work of the BSD port, and initially has the same functionality. Today's contribution simply modifies the build process to create universal binary, and produces a .jdk bundle which is recognized by Java Preferences and the JVM detection logic in Mac OS X.You will find a list of important links in regard of this project in the announcement mail. ]]> Wed, 12 Jan 2011 20:42:30 +0100 http://www.c0t0d0s0.org/archives/7133-guid.html http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/7133-Apple-start-to-make-public-contributions-to-OpenJDK.html Firesheep and the SSL everywhere route - Solaris and SPARC may be of help http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/VOaJf_TYjpI/6986-Firesheep-and-the-SSL-everywhere-route-Solaris-and-SPARC-may-be-of-help.html English Solaris Sun/Oracle Technology http://www.c0t0d0s0.org/archives/6986-Firesheep-and-the-SSL-everywhere-route-Solaris-and-SPARC-may-be-of-help.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=6986 19 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=6986 nospam@example.com (Joerg Moellenkamp) September 2007 when i talked about SSL acceleration and made the case for T2.

In the first few seconds i asked my self, why there is that new interest in this article. However then i just thought "Damned, Firesheep".

Just in case you didn't heard about it: With firesheep you can highjack user sessions by sniffing on unencrypted data flow in your network. This can work, as often the authentication form itself is encrypted, but afterwards they use unencrypted communication. The authorization to access those pages with your login credentials is carried forward by cookies. When you are able to gather this cookie, you can take over the session of a user. This isn't really a new attack vector, but firesheep is makes this really easy ... script-kiddies easy. It's integrated into Firefox as a plugin and hijacking other peoples session is as easy as changing tabs.When you want an explanation for that, please look at Eric Butlers preso "Hey Web 2.0:Start protecting user privacy instead of pretending to". The attack vector bases on the fact that someone can sniff your data. You may think at first "Well, we have switches, no sniffing", however think about unencrypted (and i consider WEP as unencrypted) WLANs.

There is just one solution: Encrypt everything. HTTPS to the help. However while this isn't a problem on client side, it creates a lot of problems on the server side. Like the problem, that virtual hosts are in need of their own IP addresses (there is an Hen-Egg-Problem in SSL). Or that you have to provide the other end of the cryptographic connection, thus you have to do all the calculation on the server side.

I'm still pretty sure, that SPARC T-class and Solaris can really help you here. The T-Series because of it's cryptographic unit. It isn't just an rather small extension like the additional commands in Nehalem to accelerate AES, it's a full-fledged crypto co processor. In the case of the SPARC T3 you have 16 of them and they got some significant update to accelerate mor ciphers and to handle many small packets much better. There is an interesting presentation availble about this piece of silicon in T3. It's already the 3rd generation of crypto acceleration in T3.

However hardware is nothing without software and thus i want to point you view to kssl. kssl is an in-kernel proxy for SSL. This in-kernel proxy uses the hardware acceleration in the T3 via the Solaris Cryptographic Framework (SCF), another nice thing that does the abstraction between the hardware (or non-existing hardware, when you do cryptography on your normal CPU) and the services using cryptography. Why is the in-kernel proxy that useful? At first it's easy to configure, but more important you don't have to hop between user- and kernelspace, as when a usermode library like openssl uses the kernel driver of your hardware. This gives you additional performance.

This kssl and SCF thing is however nothing that's limited to T-class. It's available on x86-solaris as well and in the case you purchase a supported crypto acceleration card, kssl uses this via SCF as well. However a PCI based card can never be as fast as crypto accelerators directly on die and on core like the ones in T-class. ]]> Fri, 29 Oct 2010 09:08:32 +0200 http://www.c0t0d0s0.org/archives/6986-guid.html http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/6986-Firesheep-and-the-SSL-everywhere-route-Solaris-and-SPARC-may-be-of-help.html To dedup or not to dedup - that results in a lot of questions http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/Qmck0EGu7Ag/6352-To-dedup-or-not-to-dedup-that-results-in-a-lot-of-questions.html English Solaris Sun/Oracle Technology http://www.c0t0d0s0.org/archives/6352-To-dedup-or-not-to-dedup-that-results-in-a-lot-of-questions.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=6352 8 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=6352 nospam@example.com (Joerg Moellenkamp) Continue reading "To dedup or not to dedup - that results in a lot of questions" ]]> Mon, 08 Feb 2010 20:42:41 +0100 http://www.c0t0d0s0.org/archives/6352-guid.html http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/6352-To-dedup-or-not-to-dedup-that-results-in-a-lot-of-questions.html Selfmade SSDs - or: the tale of thinking too complex .... http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/2z18ystNH60/6248-Selfmade-SSDs-or-the-tale-of-thinking-too-complex-.....html English Solaris Sun/Oracle Technology http://www.c0t0d0s0.org/archives/6248-Selfmade-SSDs-or-the-tale-of-thinking-too-complex-.....html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=6248 5 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=6248 nospam@example.com (Joerg Moellenkamp) Continue reading "Selfmade SSDs - or: the tale of thinking too complex ...." ]]> Fri, 01 Jan 2010 12:29:43 +0100 http://www.c0t0d0s0.org/archives/6248-guid.html http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/6248-Selfmade-SSDs-or-the-tale-of-thinking-too-complex-.....html Presentation at the Apache Hadoop Get Together Berlin http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/GqsAWfS5T5c/6083-Presentation-at-the-Apache-Hadoop-Get-Together-Berlin.html Solaris Sun/Oracle Technology The IT Business http://www.c0t0d0s0.org/archives/6083-Presentation-at-the-Apache-Hadoop-Get-Together-Berlin.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=6083 0 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=6083 nospam@example.com (Joerg Moellenkamp) Apache Hadoop Get Together in Berlin. The talk will be divided in three parts:
  • Advantages of using Hadoop on CMT systems like the T5120
  • Using Hadoop in conjunction with Solaris Features like Container and Resource Management in non-dedicated architectures
  • Hadoop and Grid Engine
There will be short live demonstrations in the second and third part of the presentation.

My presentation will not be the only one. Richard Hutton from nugg.ad talks about data processing with hadoop in his presentation "Moving from five days to one hour." Nikolaus Pohle from Nurago talks about data analysis with Hadoop for online market research. ]]> Fri, 06 Nov 2009 22:09:09 +0100 http://www.c0t0d0s0.org/archives/6083-guid.html http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/6083-Presentation-at-the-Apache-Hadoop-Get-Together-Berlin.html About that data loss at Microsoft/Danger http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/oHaEnPqa3Mw/6028-About-that-data-loss-at-MicrosoftDanger.html English Solaris Sun/Oracle Technology The IT Business http://www.c0t0d0s0.org/archives/6028-About-that-data-loss-at-MicrosoftDanger.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=6028 3 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=6028 nospam@example.com (Joerg Moellenkamp)
TGDdaily started by reporting the information provided by a reader with the article: "Oracle, Linux, Sun to blame for Sidekick Danger data loss":
TG Daily reader Tommy T informed us earlier today that: “Microsoft was running on Sun Solaris/Linux/Oracle-based Danger servers at the Verizon Business Center in San Jose as part of a contractual obligation to T-Mobile.”
That isn't really a surprise. Despite all the press fuzz, many many sites still deploy and use Solaris for their mission critical stuff, while using Linux for stuff that scales well on clusters.

Of course Microsoft was asked for the reasons and just reported
Sidekick runs on Danger’s proprietary service that Microsoft inherited when it acquired Danger in 2008. The Danger service is built on a mix of Danger created technologies and 3rd party technologies.
I think that's a good answer, we don't blame anyone but we tell the world, the application wasn't developed at Microsoft and the infrastructure wasn't Microsoft as well. Especially as Microsoft doesn't need additional doubts about the feasibility of their operating and infrastructure environment after Microsoft loosed the .net implementation at the London Stock Exchange in favor of of a Solaris/Linux implementation. I don't expect Microsoft to shed more light into the situation.

And it isn't that way, that they are the only shop on the world using RAC on Sun. The Inquirer expresses this situation in a nice way - "Oracle and Sun fingered for Sidekick fiasco"
That would all be well and good but for the fact that the Sun-Oracle combo is not exactly rocket science and is popular among those who manage very large, mission critical corporate databases.
I think, the truth about this outage is much more complex, as the various media outlets state. IT systems are called systems for a reason. They are large complex interrelationships of components. There is a database, there is server, there is storage, there is a SAN, there is a network. And there are many devils of the detail in any system. Whoever says something different, simply lies.

But at the end it's pretty irrelevant. It's like with aircraft crashes. There isn't a single reason why an aircraft crash happens. When there is a major CNN moment at a service, there are several resons why it happened. It may start with a small hick-up and other effects leads to a disaster.

At the end it's a large heap of rumors surrounding this situation. Daniel Eran Dilger writes in "Microsoft’s Pink/Danger backup problem blamed on Roz Ho":
According to the source, the real problem was that a Microsoft manager directed the technicians performing scheduled maintenance to work without a safety net in order to save time and money. The insider reported:
In preparation for this [SAN] upgrade, they were performing a backup, but it was 2 days into a 6 day backup procedure (it’s a lot of data). Someone from Microsoft (Roz Ho) told them to stop the backup procedure and proceed with the upgrade after assurances from Hitachi that a backup wasn’t necessary. This was done against the objections of Danger engineers.
As far as I'm understanding the rumor, they made a backup, deleted they only other backup in the course of this procedure, stopped the backup and did a firmware update. Sorry ... i don't even do an update of of notebook without starting a backup before doing so and my blog replicates it data every six hours to a system in my office at home.

A backup is a safety net. You don't do any task that could put your data at risk without having an backup. And you should better test the restore. Of course this takes time, at my blog a few minutes ... at Danger a few days. But you are sure that you don't appear at CNN. (okay, i would appear at CNN, but i would get some question in our coffee kitchen at work). Sh.t happens, customers understand this, but they don't accept that you don't value their data. Perhaps this is the real story of the this mishap.

“In preparation for this [SAN] upgrade, they were performing a backup, but it was 2 days into a 6 day backup procedure (it’s a lot of data). Someone from Microsoft (Roz Ho) told them to stop the backup procedure and proceed with the upgrade after assurances from Hitachi that a backup wasn’t necessary. This was done against the objections of Danger engineers.
I really can't imagine a single reason why a HDS/HP/EMC/Sun storage support engineer says "Hey. You don't need a backup. We will do the firmware upgrade without it". I just can imagine that the the engineer said: "Well ... i did several upgrades so far and there wasn't a problem that sent me to the tapes"

By the way: There is one thing, that keeps me really puzzled. It's a piece of information at TheRegister:
It involves 20 or so CentOS Linux servers [...]
Sorry, CentOS is a nice variant of Linux, but i don't really think that's a good idea to use a distribution of Linux with at least questionable commercial support (The "Commercial Support" menu item at centos.org delivers a page stating that there is no content) in a mission critical environment. I know that an enterprise Red Hat or Suse distribution/support agreement costs you some bucks, but in such an environment i would opt for the professionally supported variant. But again: This is a example of an attitude. And this attitude is not one of valuing the data of the users.

A hickup in a service has most often their reason in the realm of technology, but real disaster has more reasons, it has deeper reasons. Just 10% are technological reasons. Or to say it more precisely: A disaster can be root caused by a technical reason, but the step from a hickup to a disaster needs always reasons outside the realm of technology. And given the rumors surrounding the Danger outage are true, this outage is one of the best examples to show it. ]]> Tue, 20 Oct 2009 15:48:00 +0200 http://www.c0t0d0s0.org/archives/6028-guid.html http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/6028-About-that-data-loss-at-MicrosoftDanger.html Sun Storage F5100 officially announced http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/dBZjPZYLt2w/6003-Sun-Storage-F5100-officially-announced.html English Solaris Sun/Oracle Technology http://www.c0t0d0s0.org/archives/6003-Sun-Storage-F5100-officially-announced.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=6003 7 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=6003 nospam@example.com (Joerg Moellenkamp) Sun Storage F5100 Flash Array. Furthermore the documentation of this devices should reappear soon at docs.sun.com. Until that moment you will find some additional information about the device at Sun's website. This device isn't that expensive as you may think. The device starts at $45,995 (with 20 Flash Modules giving you 480 GB, 397 K IOPS read and 304 K IOPS write).

When you look in such a device you will see 80 densly packed FMods.

In the back of the device you will find the SAS connectors for the device. There are four domains with 4 SAS connectors each. For a maximum performance configuration you configure 5 FMods and a SAS connector into a zone.

Most important: The FMods doesn't have a battery on each module to protect the caches. This is done centrally by super capacitors in so called Energy Storage Modules. You plug them into the front of these devices.

Just a warning: Those ESM are quite potent super caps. Read the manual with care before handling those modules. You need a lot of power to protect all the caches and those ESM are capable to deliver this power. ]]> Mon, 12 Oct 2009 08:48:30 +0200 http://www.c0t0d0s0.org/archives/6003-guid.html http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/6003-Sun-Storage-F5100-officially-announced.html Observations on memory reliability http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/tliGaaosrKc/6001-Observations-on-memory-reliability.html English Technology The IT Business http://www.c0t0d0s0.org/archives/6001-Observations-on-memory-reliability.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=6001 5 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=6001 nospam@example.com (Joerg Moellenkamp) storagemojo (BTW: Robins blog is really a great read). He points to the paper "DRAM Errors in the Wild: A Large-Scale Field Study"( written by Bianca Schroeder (University of Toronto), Eduardo Pinheiro and Wolf-Dietrich Weber (both from Google)) in his article.

Some of the numbers are really terrifying: 4.15% unrecoverable errors for of of the platforms are much more then i had thought and i'm somewhat conservative in my thinking how far i trust hardware. Furthermore hard errors (as in "bit permanently flipped and put it to the trashbin") are vastly more common reasons for errors as most people think.

As a sidenote: After the discussion about DRAM prices in the M3000 i've got some flak because of memory prices at different quality and got many comments "there never failed a dimm at my home pc". But given the point that Google is said to use cheaper hardware and the amount of errors (especially the unrecoverable ones) there may be a point behind the fixation of Sun in regard of memory quality ]]> Sun, 11 Oct 2009 20:48:56 +0200 http://www.c0t0d0s0.org/archives/6001-guid.html http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/6001-Observations-on-memory-reliability.html Somewhat stable Solid State http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/3BW_DW9t_O4/5993-Somewhat-stable-Solid-State.html English Sun/Oracle Technology http://www.c0t0d0s0.org/archives/5993-Somewhat-stable-Solid-State.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=5993 44 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=5993 nospam@example.com (Joerg Moellenkamp) Continue reading "Somewhat stable Solid State " ]]> Fri, 09 Oct 2009 12:33:00 +0200 http://www.c0t0d0s0.org/archives/5993-guid.html http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/5993-Somewhat-stable-Solid-State.html Different CPU, same challenges http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/fi4abbAgams/5987-Different-CPU,-same-challenges.html English Technology The IT Business http://www.c0t0d0s0.org/archives/5987-Different-CPU,-same-challenges.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=5987 20 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=5987 nospam@example.com (Joerg Moellenkamp)
BlueToTheBone writes in his column "The Four Hundred" about Moore's Law and the Performance Wall:
Well, with the Power7 chips coming next year, IBM has to get the multithreading fixed in DB2 for i or get a whole lot of excuses ready for why customers buy more cores and threads, running at lower clock speeds, and don't see performance go up.
But he points to an even more interesting point, that isn't really a known territory to an open systems guy like me. Besides of this "bytecode-compiled is slower than iron-compiled" stuff (which isn't true since the invention of Just-in-time-compilers) he has a very valid point. Much of the software is really old, and it wasn't written for a environments with hundreds of cores. We learned the hard way, that there were a vast amount of pitfalls in the Open System world which thinks multithreaded/multiprocess for quite a time now. Now software developed in RPG and COBOL (and many code lines originate from a time when many of us weren't even a glint in the eyes of our parents) hits with Power7 on an environment that doesn't fulfill on the promise of ever-increasing single-thread performance. BlueToTheBone comes to a similar conclusion than the one i've made a while ago. Perhaps many applications stay on Power6 while newer developments can move to Power7:
. It might even mean putting off a move to Power7 iron and sticking with Power6 or Power6+ boxes as you dig through your code and see how parallelization can and cannot be used to make your applications run faster as well as offer more capacity to support more work.
]]> Tue, 06 Oct 2009 11:57:54 +0200 http://www.c0t0d0s0.org/archives/5987-guid.html http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/5987-Different-CPU,-same-challenges.html Me too! http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/zcZMS1d0Xi0/5986-Me-too!.html English Technology The IT Business http://www.c0t0d0s0.org/archives/5986-Me-too!.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=5986 9 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=5986 nospam@example.com (Joerg Moellenkamp) "We have it, too - kind of" from Armonk. They tout their product IBM DB2 Pure Scale. Power machines with AIX, some infiniband gearand special edition of DB2.

Some educated guesses

Mr. BlueToTheBone is right. Details are sparse at the moment. But just to write down some points, you remember for having a deeper look at after an official announcement. Those points are purely speculative given that the information in the ElReg article are really sparse:
  • It will be interesting how this solution with a centralized lock management will compare with the distributed lock management in RAC. Perhaps this will be the scaleability stopper for the IBM solution. I think we will see a solution with fewer, but bigger nodes. Given that the job of lock management is consolidated on one node, i would say that the front end node will be a really big machine.
  • But have the same opinion like Chris Mellor (hell freezes over, i have the same opinion): IBM has a storage problem. There was the 1 Million IOPS Quicksilver marketing stunt. But that system were just 40 Fusion-IO cards in a lot of servers. So that doesn't look like something playing in the same ballpark like the Sun F5100
    The QuickSilver flash was composed of one or two 250GB Fusion-io ioDrives with PCIe interfaces in 29 host servers connected by Fibre Channel to the 13 SVCs. There were 41 ioDrives in total.
    Just for the uninitated: The SVC (Storage SAN Volume Controller) is a server as well. A full rack of hardware for 1 Million IOPS. But perhaps they just plug the Fusion-IO in the database servers and don't use SVC at all... who knows
  • The p6 pSeries systems doesn't have PCI Express 2.0. With the PCIe 1.0 variant you have 240 MBytes/s. Thus you have somewhat around 2 GByte/s on the x8 PCIe of a p520 for example. That isn't enough for QDR. Some systems like the 520 provide GX busses for better connectivity, but nevertheless there doesn't seem to be QDR cards supported in the systems. But those 520 are 4 RU systems, don't know if they use them for such a cluster. Thus i would expect to see DDR infiniband in those systems. I assume they will have half the bandwidth in the fabric
  • There isn't a system in the pSeries lineup that allows to put 12 disks on 2 rack units. That's the other side of the storage problem, albeit Chis Mellor at El Reg doesn't mention it. That's the point why the X4275 is such an interesting system. You can have 12 Disks and 2 sockets on 2 rack units. I assume the database servers have seperate storage arrays.

There are some other points, but those are much deeper in the realm of speculation, so i just wait for the announcement for further comments.

Frankenbase

Some people say, that Exabyte V2 in its current incarnation is just rushed together in the light of the upcoming merger. But the stuff that IBM told exclusively in the ears of Bluetothebone sounds like kludged together just to counter an competitors announcement. I'm sure that IBM will show of a strange configuration, calling it DB2 Pure Scale. But Frankenstein creation will look as a beauty beside this solution. ;-)

]]> Mon, 05 Oct 2009 15:19:17 +0200 http://www.c0t0d0s0.org/archives/5986-guid.html http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/5986-Me-too!.html Guide to AES http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/zj6OMb-fOfk/5961-Guide-to-AES.html English Security Technology http://www.c0t0d0s0.org/archives/5961-Guide-to-AES.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=5961 2 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=5961 nospam@example.com (Joerg Moellenkamp) "Stick Figure Guide to the Advanced Encryption Standard (AES)". A really great explanation of AES. ]]> Sat, 26 Sep 2009 10:40:53 +0200 http://www.c0t0d0s0.org/archives/5961-guid.html http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/5961-Guide-to-AES.html Fun with VoIP http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/T26_RwSn63U/5952-Fun-with-VoIP.html English Technology http://www.c0t0d0s0.org/archives/5952-Fun-with-VoIP.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=5952 1 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=5952 nospam@example.com (Joerg Moellenkamp) The Annoyatron Telemarketer Torture. I want this on my cellphone when someone calls me to sell me a private health insurance. Well ... as i switch into "maximum unfriendliness", they don't call me often ... looks like i have some negative mark in their data warehouse ;-) ]]> Wed, 23 Sep 2009 07:38:34 +0200 http://www.c0t0d0s0.org/archives/5952-guid.html http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/5952-Fun-with-VoIP.html The new TPC-H benchmark from IBM http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/SgDSBJsANzk/5941-The-new-TPC-H-benchmark-from-IBM.html English Technology The IT Business http://www.c0t0d0s0.org/archives/5941-The-new-TPC-H-benchmark-from-IBM.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=5941 9 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=5941 nospam@example.com (Joerg Moellenkamp)
But i will go into the past before: In 2007 (in IT thats halfway to infinity) Sun benchmarked the E25K with 72 sockets at 1.8 GHz with two cores per socket and 256 GBytes of memory. This benchmark yielded 114,713.7 QphH.

2 years, 224 GBytes main memory and 3.2 GHz later the biggest machine available from IBM is just 34 percent faster (to be exact: 154,115.8 QphH) than the biggest machine available from Sun from two years ago ... based on a design from the beginning of this century.

By the way: Just in case you wonder about the memory configuration - 512 GB is the maximum configuration that can be used with 667 MHz. More downclocks the memory. Using 4 TB of memory would downclock it to 400 MHz.

Perhaps the challenge gets a little more clear, when we stay in the same shop: Almost 4 years ago IBM published a result of the p5-595. This system yielded with 1.9 Ghz Power5 CPU 100,512.30 QphH. 4 years of development, 256 GByte more memory and 2.6 times the frequency gives you just roundabout 50% more performance. Nice, but not that impressive, especially given the effort put into this CPU in regard of cycles.

An thats perhaps the most important takeaway from this point: Ingo was right. Just increasing the frequency isn't sufficient. It gets clearer with every published benchmark. You have to do more or different. Perhaps the future of large SMP systems is in a more efficient communication between the components, more real bandwidth (not all bandwidths added into a number for marketing purposes) and less bandwidth between the CPUs and between CPU and bandwith.

But i have a request to our benchmarking team: I would like to see an TPC-H result for the M9000 at 3TB. Giving the existing results for the M9000, putting some knowledge into the equation and doing some extrapolations i don't think that that we have to fear this competition. But thats just an educated guess. ]]> Sun, 20 Sep 2009 21:09:58 +0200 http://www.c0t0d0s0.org/archives/5941-guid.html http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/5941-The-new-TPC-H-benchmark-from-IBM.html BlueToTheBone, Sun, SGI and the SPECjbb2005 benchmark http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/MkWWXaWrB78/5937-BlueToTheBone,-Sun,-SGI-and-the-SPECjbb2005-benchmark.html English Sun/Oracle Technology The IT Business http://www.c0t0d0s0.org/archives/5937-BlueToTheBone,-Sun,-SGI-and-the-SPECjbb2005-benchmark.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=5937 1 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=5937 nospam@example.com (Joerg Moellenkamp) BlueToTheBone tries to downplay everything coming Sun, even when doing so makes a complete fool out of him.

Continue reading "BlueToTheBone, Sun, SGI and the SPECjbb2005 benchmark" ]]> Fri, 18 Sep 2009 23:03:00 +0200 http://www.c0t0d0s0.org/archives/5937-guid.html http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/5937-BlueToTheBone,-Sun,-SGI-and-the-SPECjbb2005-benchmark.html Flash in the Oracle Exadata V2 http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/4FuT4ZHuFEY/5921-Flash-in-the-Oracle-Exadata-V2.html English Sun/Oracle Technology The IT Business http://www.c0t0d0s0.org/archives/5921-Flash-in-the-Oracle-Exadata-V2.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=5921 3 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=5921 nospam@example.com (Joerg Moellenkamp) FAQ page of the Exdata system:
2 quad-core Intel Xeon E5540 (2.53GHz) processors 24GB memory
4X96 GB Sun Aura Smart Flash Accelerator F20 PCU cards
Disk Controller HBA with 512MB Battery Backed Write Cache
InfiniBand Connectivity Dual-Port QDR (40Gb) InfiniBand Host Channel Adapter
Power Supplies - Dual-redundant, hot-swappable
Remote Management Sun Embedded Integrated Lights Out Manager (ILOM)
Disk Drives 12 x 600 GB 15,000 RPM SAS.
The flash drive isn't in the disk slots, it's on this cards. Thus each of the cells comes with 384 GB of flash. You don't have to sacrify space for speed here. Neat. ]]> Wed, 16 Sep 2009 09:11:37 +0200 http://www.c0t0d0s0.org/archives/5921-guid.html Infiniband oracle sun http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/5921-Flash-in-the-Oracle-Exadata-V2.html The Oracle/Sun announcement of Exadata Version 2 http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/2mZGBpW0juM/5920-The-OracleSun-announcement-of-Exadata-Version-2.html English Sun/Oracle Technology The IT Business http://www.c0t0d0s0.org/archives/5920-The-OracleSun-announcement-of-Exadata-Version-2.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=5920 0 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=5920 nospam@example.com (Joerg Moellenkamp)

Neat sticker

But let's start at the beginning. Oracle and Sun (still two totally separate companies, there are two brand logos on the systems ;-) ) announced yesterday a new version of the Exadata system.



Evolution

The announcement states in Marketinginese:
The result is a quantum leap in performance over Oracle's previous generation Exadata machine, including a 20x increase in random I/O and a 5x I/O bandwidth speedup with FlashFire Technology, as well as a 2x speedup in compute and network performance capacity. In short, the Exadata Version 2 is the world's fastest machine for both data warehousing and online transaction processing.

It's a Nehalem based system running on Oracle Enterprise Linux. This system uses 40 GBit/s Infiniband instead of the 20 GBit/s variant. It uses Nehalem instead of of the Core2 based Xeons. Provides 72 GB instead of 24 GB main memory. I would summarize it as some evolutionary changes to the system while adding flash memory to the equation as larger step of development.

A product isn't just hardware and software

Yes, my heart is bleeding, too. Yes, i would have liked to see a SPARC based system with Solaris as well. But we have to see this realistic. You have a running and established product (the Exadata V1 system) running on HP components. You plan to buy a large hardware vendor. What do you do? Yes, you stop to use the components of a company that is possibly a competitor in the near future and use those components from a company you will own in the future.

I should tell you something about making products: Don't change too many things at once when you already have a product. Each change has to be evaluated, evaluation takes time. So at first yield the quick-wins. And in this case it was swapping the hardware. Selling a product is more than just having a running system, it's about training the support organisations, it's about the knowledge of to implement it, this takes time. Step by step has it's advantages. And by the way: There are infinite numbers above 2 in the set of natural numbers ;-)

It's an OR, not a XOR

Interestingly there are some news outlets interpreting the fact as contrary to the ad at the WSJ. You have two ways to interpret this announcement: Oracle changed their mind about SPARC and just wants to do x86 and the SPARC thing was just a joke. Sorry, what a large heap of bullshit. The other way to see this is much more positive and it's somewhat like an additional commitment: "Oh, Oracle uses the x86 gear of Sun".

But i have to assume, that isn't such good headline line like the of of BlueToTheBones of SPARC missing in action. And sorry Oracle ... it's a RAC beneath it ... and it has it's own share of problems on non-disjunct data enabling you to shard the data (Albeit it's not that problematic with Infiniband than in the times when people used 100 MBit/s or 1GbE for the RAC interconnect). At the end the idea Workload Computing still holds true. It's not a XOR, it's an OR of both technologies.

Conclusion

Reading those news outlets these days is more and more just an outright and major annoyance. At the end just two further comments:
  • By the way, the HP based Exadata appliance used x86 and not Itanium, OEL instead of HPUX. You get it ? ;-)
  • 2. There will be other announcements. One announcement was already announced ... kind of ;-)
]]> Wed, 16 Sep 2009 08:34:05 +0200 http://www.c0t0d0s0.org/archives/5920-guid.html Infiniband oracle solaris sun http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/5920-The-OracleSun-announcement-of-Exadata-Version-2.html The impact of virtualisation http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/zDybMieal8U/5917-The-impact-of-virtualisation.html English Solaris Sun/Oracle Technology The IT Business http://www.c0t0d0s0.org/archives/5917-The-impact-of-virtualisation.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=5917 5 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=5917 nospam@example.com (Joerg Moellenkamp) Jan searched a little bit in the large heap of benchmarking certifications of SAP and found something really interesting. The benchmarks certified in document number 2009034 (Sun Fire X4270, 2 processors /8 cores / 16 threads, Intel Xeon Processor X5570, 2.93 GHz, 64 KB L1 cache and 256 KB L2 cache per core, 8 MB L3 cache per processor, 48 GB main memory) yielded 15,320 SAPS on 8 vCPU. On the other side an Fujitsu PRIMERGY Model RX300 S5 (2 processors / 8 cores / 16 threads, Intel Xeon Processor X5570, 2.93 GHz, 64 KB L1 cache and 256 KB L2 cache per core, 8 MB L3 cache per processor, 96 GB main memory) yielded 11,230 SAPS (as certified by 2009029). I should add something ... in my opinion it's not the system, that was responsible for this large gap. So what's the difference?

Both benchmarks included an virtualisation layer. Both systems were limited to use 8 vCPU for the central server. And here is the difference: The Sun system used Containers on Solaris 10 with Oracle 10g and started the central server in a non-global zone. The Fujitsu system used SLES 10 with MaxDB as a VMware ESX 4.0 VM. Based on this benchmark, it looks like that the containerized system is able to yield 136 percent of the performance of the VMware-virtualized system. 35 percent performance are a quite significant difference. ]]> Mon, 14 Sep 2009 16:09:03 +0200 http://www.c0t0d0s0.org/archives/5917-guid.html oracle solaris sun http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/5917-The-impact-of-virtualisation.html RBridges integrated to Opensolaris Build 124 http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/QM6uGmxeuGc/5912-RBridges-integrated-to-Opensolaris-Build-124.html English Solaris Sun/Oracle Technology http://www.c0t0d0s0.org/archives/5912-RBridges-integrated-to-Opensolaris-Build-124.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=5912 1 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=5912 nospam@example.com (Joerg Moellenkamp)
One of it's components is the RBridge - the routing bridge. I've heard the first time at the CEC 2007 about this concepts when Radia Perlman held a talk in the "Luminaries"-Track.

Hmm ... i know it's the oversimplification of the year, but the basic idea of TRILL and RBriges is the usage of well-proven IP routing protocols and their mechanisms to build optimal routing tables to the domain of bridging and thus getting rid of the STP. STP is an proven and venerable concept, but it has many shortfalls: slow convergence against topology changes (vulgo: cable or switch fails) especially when you use it in it's pure form, the problem of multiple paths (As STP is a tree, it forces all traffic on one line and it's not using alternate links, when you do something like that you have to work with multiple spanning trees in seperate VLANs), furthermore the traffic flows aren't optimal.

RBridges try to solve those problems. When you want to know more about this i just want to link you to the Infocom 2004 paper by Radia describing the concept, the RFC with the problem statement and the base specification of the RBridges. I just want to quote the abstract of the last document to give you an impression what the IETF wants to accomplish with this routing bridges:
RBridges provide optimal pair-wise forwarding with zero configuration, safe forwarding even during periods of temporary loops, and support for multipathing of both unicast and multicast traffic. They achieve these goals using IS-IS routing and encapsulation of traffic with a header that includes a hop count.
RBridges are compatible with previous IEEE 802.1 customer bridges as well as IPv4 and IPv6 routers and end nodes. They are as invisible to current IP routers as bridges are and, like routers, they terminate the bridge spanning tree protocol.
The design supports VLANs and optimization of the distribution of multi-destination frames based on VLAN and IP derived multicast groups. It also allows forwarding tables to be sized according to the number of RBridges (rather than the number of end nodes), which allows internal forwarding tables to be substantially smaller than in conventional bridges.
Why do i tell you all this stuff: Those RBridges found their way into OpenSolaris with the putback of the code from of the developments efforts from the Bridging Project (PSARC 2008/055 and PSARC 2009/344) and the RBridge Project (PSARC 2007/596). You can read more about this new developents that were integrated to Build 124 today at the webpages of the ARC cases. ]]> Thu, 10 Sep 2009 22:19:40 +0200 http://www.c0t0d0s0.org/archives/5912-guid.html solaris http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/5912-RBridges-integrated-to-Opensolaris-Build-124.html Thoughts about this DIY-Thumper and storage in general http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/NOJZ7zMXYkI/5906-Thoughts-about-this-DIY-Thumper-and-storage-in-general.html English Solaris Sun/Oracle Technology The IT Business http://www.c0t0d0s0.org/archives/5906-Thoughts-about-this-DIY-Thumper-and-storage-in-general.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=5906 15 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=5906 nospam@example.com (Joerg Moellenkamp) "Some perspective to this DIY storage server mentioned at Storagemojo". I wrote that article after reading Robin Harris' article about a DIY high density storage server. Thanks to Google Translate even those in russian language (i've realized that my french is still good enough to read through texts, albeit i have to admit that reading a text in french written by me would be an even more horrible experience than a text in english). Just a warning at the beginning. This text is 32 hard disk marketing KBytes long. 31 of the real ones ;-)

Introduction

Okay, the following article isn't really about this Backblaze device, it's more about some misunderstandings regarding storage. For every suggestion i will make in this article, i see a reason why Backblaze didn't go this way. But everyone who just looks at the price and think of Sun Hardware as gold-plated, should rethink. Because for everything Sun (or other storage vendors) did at their devices, there are several good reasons as well.

The only think i've really hated about this article at Backblaze was this figure about the costs. Many people just reposted this figure but not the statement that clearly said, that this isn't a general purpose device. Without their software this storage pod would be just an horrible example to explain how you shouldn't design storage. With their software it's may be an adequate solution for their special needs and workload, and just for their special needs and their workload. No wonder, as the just developed this software for this use case.
Continue reading "Thoughts about this DIY-Thumper and storage in general" ]]> Thu, 10 Sep 2009 20:12:00 +0200 http://www.c0t0d0s0.org/archives/5906-guid.html english solaris storage sun sun/oracle technology the it business http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/5906-Thoughts-about-this-DIY-Thumper-and-storage-in-general.html Latency matters http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/1sW10DALtJM/5901-Latency-matters.html English Solaris Sun/Oracle Technology The IT Business http://www.c0t0d0s0.org/archives/5901-Latency-matters.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=5901 13 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=5901 nospam@example.com (Joerg Moellenkamp)
This latency thing wasn't such a problem in the past. You've only talked about it, when cabling over longer distances (100km for example) came into the focus. But with the increased popularity of SSD this starts to be a problem. No ... it's already a problem. I just want to guide you through a thought game to show you this challenge.
Continue reading "Latency matters " ]]> Fri, 04 Sep 2009 21:26:17 +0200 http://www.c0t0d0s0.org/archives/5901-guid.html storage http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/5901-Latency-matters.html Some perspective to this DIY storage server mentioned at Storagemojo http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/Wj5zHr0oERw/5899-Some-perspective-to-this-DIY-storage-server-mentioned-at-Storagemojo.html English Solaris Sun/Oracle Technology The IT Business http://www.c0t0d0s0.org/archives/5899-Some-perspective-to-this-DIY-storage-server-mentioned-at-Storagemojo.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=5899 27 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=5899 nospam@example.com (Joerg Moellenkamp) "Cloud storage for $100 a terabyte", which referred to the company Backblaze, which constructed a storage server on its own and described it on their blog in the article "Petabytes on a budget: How to build cheap cloud storage". Sorry, that this article took so long and there may be a higher rate of typos, as my sinusitis came back with a vengeance ... right in the second week of my vacation. But now this rather long article is ready :-)

Continue reading "Some perspective to this DIY storage server mentioned at Storagemojo" ]]> Thu, 03 Sep 2009 15:22:58 +0200 http://www.c0t0d0s0.org/archives/5899-guid.html english solaris storage sun/oracle technology the it business http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/5899-Some-perspective-to-this-DIY-storage-server-mentioned-at-Storagemojo.html Sun Storage F5100 Flash Array http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/zLwbnFyTbJM/5897-Sun-Storage-F5100-Flash-Array.html English Solaris Sun/Oracle Technology The IT Business http://www.c0t0d0s0.org/archives/5897-Sun-Storage-F5100-Flash-Array.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=5897 9 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=5897 nospam@example.com (Joerg Moellenkamp) 141484-01 was released a few days ago. Yesterday the news broke about some documents at docs.sun.com about an interesting upcoming device. Now Storagemojo wrote about it
Kudos to the Sun engineers who have been driving flash forward faster than almost anyone else in the industry.
as well as Octave Orgeron in his blog who stated
This will be Sun's first step into selling products that could very well change the storage landscape.
Perhaps those was fueled by this teaser blog entry yesterday, but there was an other article about it at blogs.sun.com. Looks i'm not the only one traversing docs.sun.com at a regular schedule. ;-)

This device is really something really interesting, but i won't write more about it until it's officially announced. Oh ... just one teaser question: What's the really slow and performance-annihilating part at swapping virtual memory from/to disk? ]]> Wed, 02 Sep 2009 20:22:06 +0200 http://www.c0t0d0s0.org/archives/5897-guid.html storage sun http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/5897-Sun-Storage-F5100-Flash-Array.html Rainbow Falls http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/HVkuqZb1qlM/5884-Rainbow-Falls.html English Sun/Oracle Technology http://www.c0t0d0s0.org/archives/5884-Rainbow-Falls.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=5884 7 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=5884 nospam@example.com (Joerg Moellenkamp)

It gives you some interesting insight into the future development the the next gen CMT procs. His presentation focuses on the challenges you are facing, when you double the core count. ]]> Wed, 26 Aug 2009 19:25:34 +0200 http://www.c0t0d0s0.org/archives/5884-guid.html http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/5884-Rainbow-Falls.html Hotchips: Sun's 3rd generation on-chip UltraSPARC security acclerator http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/61gpyBmLP4M/5881-Hotchips-Suns-3rd-generation-on-chip-UltraSPARC-security-acclerator.html English Sun/Oracle Technology http://www.c0t0d0s0.org/archives/5881-Hotchips-Suns-3rd-generation-on-chip-UltraSPARC-security-acclerator.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=5881 7 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=5881 nospam@example.com (Joerg Moellenkamp)


The presentations digs deep into the technical reasoning and implementation of the encryption facilities of RF. Really worth a read.

But there is more in the presentation. Several slides hints to features of the Rainbow Fall, e.g.: RF will contain a instruction for IP Checksum Generation (useful for IPsec), it will have 16 crypto accelerators, 8 strands per core ... but read it on your own :-) ]]> Wed, 26 Aug 2009 08:50:12 +0200 http://www.c0t0d0s0.org/archives/5881-guid.html http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/5881-Hotchips-Suns-3rd-generation-on-chip-UltraSPARC-security-acclerator.html Forrester about the future of storage http://feedproxy.google.com/~r/C0t0d0s0org-Technology/~3/SAHu_DUPJG4/5864-Forrester-about-the-future-of-storage.html Computing English Sun/Oracle Technology The IT Business http://www.c0t0d0s0.org/archives/5864-Forrester-about-the-future-of-storage.html#comments http://www.c0t0d0s0.org/wfwcomment.php?cid=5864 0 http://www.c0t0d0s0.org/rss.php?version=2.0&type=comments&cid=5864 nospam@example.com (Joerg Moellenkamp) waning importance of storage array controllers.. I'm argued that we will see different storage concepts in the future, whereas the reader was pretty sure, that the storage controllers will play the same role in the future than today and that's just Sun who thinks differently (at least that was my understanding of his comments)

Yesterday i found the following article of the Storageractice of Sun Taiwan: They cite in 你還需要儲存區域網路嗎 a study of Forrester about the future of storage. My colleagues in Taiwan posted a single slide of this document. And the slide is really interesting, as it supports some of my arguments in regard of the future development of storage.
Continue reading "Forrester about the future of storage" ]]> Tue, 18 Aug 2009 21:40:47 +0200 http://www.c0t0d0s0.org/archives/5864-guid.html storage sun http://creativecommons.org/licenses/by-sa/2.5/ http://www.c0t0d0s0.org/archives/5864-Forrester-about-the-future-of-storage.html