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nospam@example.com (Joerg Moellenkamp) — Tue, 15 May 2012 12:53:22 +0200

IOPS, capacity, bandwidth - and something new to explain to the people in purchasing

nospam@example.com (Joerg Moellenkamp) — Sat, 28 Apr 2012 11:59:58 +0200

When you size storage, you have to size for three things: IOPS, capacity and bandwidth. But that has an interesting implication. When we had 2,4 or 9 GB harddisks we needed many disks to provide the needed capacity and thus had often enough IOPS for the tasks of that time without needing further provisions. Then disks got bigger, and we created massive storage arrays with much to large capacity , but we did it for the IOPS. Now we have SSD in the TB range and with IOPS north of 100.000 and you would think that your problems are gone, however now the third parameter comes into the game: Bandwith.

So far you had often enough disks (either because of bandwidth or IOPS requirements) and thus enough raw bandwidth at least at the point right behind the disk). However it doesn't matter, when you have 1 TB and 100.000 IOPS, you still have just a storage connection that limits your transmission at 6 GBps, come hell or high water. So after explaining "No, a 1 TB USB disk from el-cheapo-component-shack isn't enough for the 1 TB database, because of IOPS yadda yadda yadda" to the people in the purchasing department, we probably have to start to explain "No, the 1 TB SSDs aren't enough as well, because of the bandwidth requirements yadda yadda yadda"

Köhlbrand Bridge

nospam@example.com (Joerg Moellenkamp) — Mon, 23 Apr 2012 10:08:30 +0200

Swap

nospam@example.com (Joerg Moellenkamp) — Wed, 18 Apr 2012 07:46:03 +0200

Seemingly simple topics are never simple. Just collecting some stuff about the topic "Swap. How to size it". Well ... it isn't simple ... not at all. Especially when you want to explain, not just giving a rule of thumb ...

River

nospam@example.com (Joerg Moellenkamp) — Tue, 17 Apr 2012 12:54:15 +0200

Upcoming event - Oracle Solaris 11: Whats New Since the Launch

nospam@example.com (Joerg Moellenkamp) — Sun, 15 Apr 2012 20:03:06 +0200

On April 25th an webbased event about Solaris 11 takes place: It's named Oracle Solaris 11: Whats New Since the Launch.

Agenda
9:00 a.m. PDT	Keynote: Oracle Solaris - Strategy and Update Markus Flierl, Vice President, Oracle Solaris Engineering
9:40 a.m. PDT	Oracle Solaris 11: Extreme Engineering - A Technical Update Dan Price, Senior Principal Product Engineer, Oracle Solaris Engineering Bart Smaalders, Senior Principal Product Engineer, Oracle Solaris Engineering
10:20 a.m. PDT	Customers and Partners: Why We Moved to Oracle Solaris 11 A discussion of the reasons why businesses and commercial software developers have adopted Oracle Solaris 11, from the people responsible for these decisions
11:00 a.m. PDT	Oracle Solaris: Core to the Oracle Systems Strategy John Fowler, Executive Vice President of Systems, Oracle

9:00 am PDT is 18:00 in Berlin, 17:00 in London and i assume much to late in Tokyo with 01:00 am the next day ...

Using the Support Repository for Solaris 11

nospam@example.com (Joerg Moellenkamp) — Sun, 15 Apr 2012 11:23:18 +0200

"How to Update Oracle Solaris 11 Systems Using Support Repository Updates" is a great article written by Glynn Foster in order to explain the use of the Support Repository for Solaris 11. A must read.

Veranstaltungshinweis: 2. Oracle Breakfast

nospam@example.com (Joerg Moellenkamp) — Fri, 13 Apr 2012 20:56:50 +0200

Am 26. April findet das zweite Oracle Oracle Breakfast in Hamburg in der Geschäftsstelle (Kühnehöfe 5) statt: Also Futtern mit technischem Content. Auch diesmal gibt es zwei Vorträge.

Agenda
9:30	Willkommen zum Frühstück
10:00	Solaris 11 im Detail - Einbindung in heterogene Netze (CIFS-Dienst etc.) Joerg Moellenkamp
11:30	Kaffeepause
12:00	ZFSSA praktisch Einbindung einer ZFS SA in heterogene Netze, aber wie? Vortrag & Livedemo unter VirtualBox Dirk Nitschke
13:30	geplantes Ende

Anmelden könnt Ihr euch mit einer formlosen Mail an oraclebreakfast_ham@c0t0d0s0.org. Das ist ein Forwarder an die Addresse der Kollegin, die das intern bei uns organisiert, deren Mailaddresse ich nicht unbedingt für Spammer verteilen möchte ...

Solaris 11 LKSF

nospam@example.com (Joerg Moellenkamp) — Fri, 13 Apr 2012 20:37:30 +0200

After having some discussions i now made my mind about it: In the next weeks you will see many republications of old articles in the blog as i will republish all articles in the LKSF, however checked and updated for Solaris 11 (some Opensolaris based stuff in the lksf is working slightly different, and if it's just for different package names). However this will take time, as i will do this on weekends and evenings. At the end i will just recollect them and create a Solaris LKSF pdf again.

Deep insight into the behaviour of the SPARC T4 processor

nospam@example.com (Joerg Moellenkamp) — Sat, 07 Apr 2012 15:24:07 +0200

Ruud van der Pas and Jared Smolens wrote an really interesting whitepaper about the SPARC T4 and its behaviour in regard with certain code: 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.

Performance impact of Zones.

nospam@example.com (Joerg Moellenkamp) — Thu, 05 Apr 2012 18:46:34 +0200

I was really astonished when i saw this question. Because this question was a old acquaintance from years ago, that i didn't heard for a long time. However there was it again. The question: "What's the overhead of Zones?". Sun was and Oracle is not saying "zero". We saying saying minimal. However during all the performance analysis gigs on customer systems i made since the introduction of Zones i failed to measure any overhead caused by zones. When there was overhead in that situation it was in the error of measurement.

What i saw however, was additional load intoduced by processes that wouldn't be there when you would use only one zone Like additional monitoring daemons, like additional daemons having a controlling or supervising job for the application that resulted in slighly longer runtimes of processes, because such additional daemons wanted some cycles on the CPU as well. Like additional sshd daemons, like additional init processes. So i ask when someone wants to tell me that he measured a slight slowdown, if he or she has really measured the impact of the virtualization layer or of a side effect described above.

It seems to be a little bit hard to believe, that a virtualisation technology has no overhead, however keep in mind that there is no hypervisor and just one kernel running that looks and behaves like many operating system instances to apps and users. While this imposes some limits to the technology (because there is just one kernel running you can't have zones with different kernels versions running ... obvious even to the cursory observer), but that is key to it's lightweightness and thus to the minimal overhead.
Continue reading "Performance impact of Zones."

BSD on a DUINOMITE

nospam@example.com (Joerg Moellenkamp) — Wed, 04 Apr 2012 13:57:31 +0200

Another Unix on a very small device: "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.

Configuring an NTP client in Solaris 11

nospam@example.com (Joerg Moellenkamp) — Tue, 03 Apr 2012 16:45:52 +0200

It is really easy to configure an NTP client on a plain standard Solaris 11 (that said it isn't more difficult on Solaris 10 ... it's the same procedure). So i will just give a very short walkthrough.

Continue reading "Configuring an NTP client in Solaris 11"

Solaris 11 features: nscfg

nospam@example.com (Joerg Moellenkamp) — Mon, 02 Apr 2012 09:43:00 +0200

As you may have noticed many configuration tasks around name services have moved into the SMF in Solaris 11. However you don't have to use the svccfg command in order to configure them, you could still use the old files. However you can't just edit them, you have to import the data into the SMF repository. There are many reasons for this need but the ultimate one is in the start method. I will explain that later. In this article i want to explain, how nscfg can help you with with the naming service configuration of your system.

Continue reading "Solaris 11 features: nscfg"

Future of Solaris

nospam@example.com (Joerg Moellenkamp) — Sun, 01 Apr 2012 20:01:43 +0200

Alan Coopersmith gives some interesting and important insights into the future of Solaris.

Yet another cheatsheet update ...

nospam@example.com (Joerg Moellenkamp) — Sat, 31 Mar 2012 19:18:47 +0200

Yet another update of the Solaris 11 cheatsheet. Some additions about disk devices, some bug fixes (there is one additional bug "Configuring system locale:" must be "Configuring time zone" ... will be fixed in the next version)

Linux on 8-bit

nospam@example.com (Joerg Moellenkamp) — Fri, 30 Mar 2012 14:46:03 +0200

This is nothing short of extremly cool from a technical perspective. The author has done it by writing an ARM emulator for an AVR controller and running Linux with this emulation : Linux on an 8-bit micro?.

This is definitely not the fastest, but I think it may be the cheapest, slowest, simplest to hand assemble, lowest part count, and lowest-end Linux PC. The board is hand-soldered using wires, there is not even a requirement for a printed circuit board

SPARC Power Management Article at OTN

nospam@example.com (Joerg Moellenkamp) — Sun, 25 Mar 2012 13:50:06 +0200

My colleague Karoly Vegh pointed in a tweet to a really interesting article about the usage of Power Management of SPARC T-series systems. The article explains how to use the power management, how it works, what it's able to do and how to use it in a dynamic fashion according to anticipated load patterns. You find the article "How to Use the Power Management Controls on SPARC Servers" written by by Bruce Evans, Julia Harper, and Terry Whatley on OTN.

Oracle Solaris 11 Developer Webinar Series

nospam@example.com (Joerg Moellenkamp) — Sat, 24 Mar 2012 09:24:42 +0100

Starting March 27th a number of events called "Oracle Solaris 11 Developer Webinar Series" (that said, i think they are not only interesting for developers, but for admins as well that support admins in their job) will take place by WebEx/Phone:

All events start at 9am Pacific Daylight Time (Should be 18:00 in Germany, 17:00 in UK, 01:00 in Tokyo). Of course the events are for free (before someone asks) and available for anyone who signs up. The chat is staffed with Solaris 11 Engineering Experts sitting in to answer questions. And most important: Mostly technical content and the events will be recorded.

Solaris 11 cheatsheet updated

nospam@example.com (Joerg Moellenkamp) — Fri, 23 Mar 2012 06:46:43 +0100

There is an updated version of the Solaris 11 cheatsheet.

NGN/NLUUG conferentie vj2012: Operating Systems

nospam@example.com (Joerg Moellenkamp) — Thu, 22 Mar 2012 10:51:31 +0100

On April 11th, 2012 the Spring 2012 conference with the topic overarching topic "Operating Systems" takes place in Nieuwegein near Utrecht. Besides talks about Linux, Windows and AIX, there will be a track about Solaris. I will be the first speaker in the Solaris track and giving an overview about Solaris 11 and how features interact. Later on renowned experts like Detlef Drewanz ("Lifecycle Management with Oracle Solaris 11"), Andrew Gabriel ("Solaris 11 Networking - Crossbow Project"), Darren Moffat ("ZFS: Data integrity and Security") and Casper Dik ("Solaris 11 Zones and Immutable Zones") will take over. Finally Patrick Ale of UPC Broadband talks about his experiences with Solaris 11.

When you want more information about this conference or register for it, you will find the webpage of the event at the NLUUG site.

Tutorial for Automated Installer

nospam@example.com (Joerg Moellenkamp) — Mon, 19 Mar 2012 11:31:52 +0100

Stefan Hinker wrote a nice tutorial helping you at the setup of a local install server: "Setting up a local AI server - easy with Solaris 11".

Performance impact of the new mtmalloc memory allocator

nospam@example.com (Joerg Moellenkamp) — Fri, 16 Mar 2012 08:50:44 +0100

I wrote at a number of occasions (here or here), that it could be really beneficial to use a different memory allocator for highly-threaded workloads, as the standard allocator is well ... the standard, however not very effective as soon as many threads comes into play.

I didn't wrote about this as it was in my phase of silence but there was some change in the allocator area, Solaris 10 got a revamped mtmalloc allocator in version Solaris 10 08/11 (as described in "libmtmalloc Improvements"). The new memory allocator was introduced to Solaris development by the PSARC case 2010/212.

But what's the effect of this new allocator and how does it works? Rickey C. Weisner wrote a nice article with "How Memory Allocation Affects Performance in Multithreaded Programs" explaining the inner mechanism of various allocators but he also publishes test results comparing Hoard, mtmalloc, umem, new mtmalloc and the libc malloc. Really interesting read and a must for people running applications on servers with a high number of threads.

Oracle Solaris 11 Cheatsheet

nospam@example.com (Joerg Moellenkamp) — Thu, 15 Mar 2012 08:06:47 +0100

In the last few days i created a cheat sheet for Solaris 11 ... while it's still a work in progress (it will be surely longer in the future). it's already available on OTN as part of the "Evaluating Oracle Solaris 11"-Collection . You can download the "Oracle Solaris 11 Cheat Sheet General Administration" here.

How to show off live migration with a SPARC system?

nospam@example.com (Joerg Moellenkamp) — Fri, 09 Mar 2012 17:03:43 +0100

Yesterday i had the opportunity to show Oracle VM for SPARC in front of customers in action. Not a single slide was used ... Everything was live . The following entry shows what i essentially did in this demo. Perhaps long time users of LDOMS or Oracle VM for SPARC (as they are called today) have already seen for this, however that wasn't the planned audience of this walkthrough. In this example i've configured the control domain, one guest domain, installed it with Solaris 11 and migrated it live (without service interruption) from one system to another)
Continue reading "How to show off live migration with a SPARC system?"

Cheatsheet for configuring a new nodename in Solaris 11

nospam@example.com (Joerg Moellenkamp) — Sat, 03 Mar 2012 20:39:55 +0100

In Solaris 11 the file /etc/nodename is gone. In order to change you nodename you have alter the configuration of an smf service:

root@fuchikoma:/home/jmoekamp# hostname
tachikoma
root@fuchikoma:/home/jmoekamp# svccfg -s svc:/system/identity:node setprop config/nodename = "fuchikoma"
root@fuchikoma:/home/jmoekamp# svcadm refresh svc:/system/identity:node
root@fuchikoma:/home/jmoekamp# svcadm restart svc:/system/identity:node
root@fuchikoma:/home/jmoekamp# hostname
fuchikoma

You don't have to edit config/loopback

root@fuchikoma:/home/jmoekamp# svcprop  svc:/system/identity:node | egrep "^config"        
config/nodename astring fuchikoma
config/loopback astring fuchikoma

Cheatsheet for configuring the networking in Solaris 11

nospam@example.com (Joerg Moellenkamp) — Sat, 03 Mar 2012 13:49:55 +0100

There are quite a number of changes in the procedures to configure some of the networking parameters. Many things have changed, that were just editing of a file in the past, have now command-line based tools in order to change their parameters. Before you ask: The reason for this steps are quite simple.

At first ist much easier to script the execution of a command, instead of the editing a file. I wrote a lot of those scripts in the past and from my experiences people have an infinite wisdom in creating ways and means to edit a file in a way that it breaks your automatic edting scripts. Furthermore putting all this configuration statements into SMF has an interesting consequence. In the past, it wasn't always clear to most people when a change of the configuration got active. At the time of the save, at the restart of the daemon? By using SMF it's clear. As soon as you type in svcadm refresh. Furthermore ifconfig came totally overloaded with parameters with the time. So dladm and ipadm were a very good move from my perspective.

However i know that this is maybe a strange for an long-time user, and to be honest, i was spelling many curses in front of the display, albeit i see the advantages. So i'm putting up my cheatsheet online. My colleague Detlef is planing something similar. As soon his is ready, i will linking to his as well, as i'm sure it's more complete.

With automatisms

In the datacenter it's not that useful, however when you have an Solaris VM for example on your notebook you are using for administrative purposes, it's really nice.

At first we create the network configuration profiles for the datacenter and the office.

root@tachikoma:/home/jmoekamp# netcfg create ncp datacenter
root@tachikoma:/home/jmoekamp# netcfg create ncp office

Now we have to fill both with the configuration data. At first the one for the datacenter. I think the values are speaking for themself.

root@tachikoma:/home/jmoekamp# netcfg
netcfg> select ncp datacenter
netcfg:ncp:datacenter> create ncu phys net0
Created ncu 'net0'.  Walking properties ...
activation-mode (manual) [manual|prioritized]> manual
link-mac-addr>
link-autopush>
link-mtu>
netcfg:ncp:datacenter:ncu:net0> end
Committed changes
netcfg:ncp:datacenter> create ncu ip net0
Created ncu 'net0'.  Walking properties ...
ip-version (ipv4,ipv6) [ipv4|ipv6]> ipv4
ipv4-addrsrc (dhcp) [dhcp|static]> static
ipv4-addr> 192.168.1.27
ipv4-default-route> 192.168.1.1
netcfg:ncp:datacenter:ncu:net0> end
Committed changes
netcfg:ncp:datacenter> exit
root@tachikoma:/home/jmoekamp#

Now we do the same for the office:

root@tachikoma:/home/jmoekamp# netcfg
netcfg> select ncp office
netcfg:ncp:office> create ncu phys net0
Created ncu 'net0'.  Walking properties ...
activation-mode (manual) [manual|prioritized]> manual
link-mac-addr>
link-autopush>
link-mtu>
netcfg:ncp:office:ncu:net0> end
Committed changes
netcfg:ncp:office> create ncu ip net0
Created ncu 'net0'.  Walking properties ...
ip-version (ipv4,ipv6) [ipv4|ipv6]> ipv4
ipv4-addrsrc (dhcp) [dhcp|static]> dhcp
ipv4-default-route>
netcfg:ncp:office:ncu:net0> end
Committed changes
netcfg:ncp:office> exit

Now we can just switch the networking configuration by enabling one of the both profiles:

root@tachikoma:/home/jmoekamp# netadm enable -p ncp datacenter
Enabling ncp 'datacenter'
root@tachikoma:/home/jmoekamp# ifconfig net0
net0: flags=201000843 mtu 1500 index 6
        inet 192.168.1.27 netmask ffffff00 broadcast 192.168.1.255
        ether 8:0:27:b6:1:70

Let's switch to the office profile:

root@tachikoma:/home/jmoekamp# netadm enable -p ncp office
Enabling ncp 'office'
root@tachikoma:/home/jmoekamp# ifconfig net0
net0: flags=201004843 mtu 1500 index 7
        inet 192.168.1.185 netmask ffffff00 broadcast 192.168.1.255
        ether 8:0:27:b6:1:70

Of course the networking configuration is not just the interface configuration but a lot other stuff as well, link the configuration of the DNS. That options are in the location profiles. However i don't want to activate the profile as well as the location both manually. Thus i configure an automatic activation of such configuration. In my example the datacenter profile configures an IP address of 192.168.1.27, the office profile uses DHCP which results in an IP-address out of the 192.168.1.100-199 range. Thus i'm using this for my automatic location switching. I can configure an activation mode and by choosing conditional-any this location profile will be activated automatically when any of the configured conditions are true. It's pretty simple in my case: If the IP address is 192.168.1.27, i'm in the datacenter, if not i'm in the office.

So, i'm configuring the location profile for the datacenter first. I think this is speaking for itself again, when you take the information into consideration, i gave you in the last paragraph:

root@tachikoma:/home/jmoekamp# netcfg
netcfg> create loc datacenter
Created loc 'datacenter'.  Walking properties ...
activation-mode (manual) [manual|conditional-any|conditional-all]> conditional-any
conditions> ip-address is 192.168.1.27
nameservices (dns) [dns|files|nis|ldap]> dns
nameservices-config-file ("/etc/nsswitch.dns")>
dns-nameservice-configsrc (dhcp) [manual|dhcp]> manual
dns-nameservice-domain> datacenter.c0t0d0s0.org
dns-nameservice-servers> 192.168.1.1
dns-nameservice-search>
dns-nameservice-sortlist>
dns-nameservice-options>
nfsv4-domain>
ipfilter-config-file>
ipfilter-v6-config-file>
ipnat-config-file>
ippool-config-file>
ike-config-file>
ipsecpolicy-config-file>
netcfg:loc:datacenter>
netcfg:loc:datacenter> exit
Committed changes

Now i will configure the one for the office:

root@tachikoma:/home/jmoekamp# netcfg
netcfg> create loc office
Created loc 'office'.  Walking properties ...
activation-mode (manual) [manual|conditional-any|conditional-all]> conditional-any
conditions> ip-address is-not 192.168.1.28
nameservices (dns) [dns|files|nis|ldap]> dns
nameservices-config-file ("/etc/nsswitch.dns")>
dns-nameservice-configsrc (dhcp) [manual|dhcp]> manual
dns-nameservice-domain> office.c0t0d0s0.org
dns-nameservice-servers> 192.168.1.1
dns-nameservice-search>
dns-nameservice-sortlist>
dns-nameservice-options>
nfsv4-domain>
ipfilter-config-file>
ipfilter-v6-config-file>
ipnat-config-file>
ippool-config-file>
ike-config-file>
ipsecpolicy-config-file>
netcfg:loc:office>
netcfg:loc:office> exit
Committed changes
root@tachikoma:/home/jmoekamp# netcfg

Okay, let's try this out. At first we activate the datacenter network configuration profile.

root@tachikoma:/home/jmoekamp# netadm enable -p ncp datacenter
Enabling ncp 'datacenter'

In theory, the resolv.conf should now change to nameserver 192.168.1.1. Let's check this.

root@tachikoma:/home/jmoekamp# cat /etc/resolv.conf

#
# Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
#

#
# AUTOGENERATED_FROM_SMF_V1
#
# WARNING: THIS FILE GENERATED FROM SMF DATA.
#   DO NOT EDIT THIS FILE.  EDITS WILL BE LOST.
# See resolv.conf(4) for details.

domain  datacenter.c0t0d0s0.org
nameserver      192.168.1.1

Okay, that was successful. Now we will switch to the network configuration profile office.

root@tachikoma:/home/jmoekamp# netadm enable -p ncp office
Enabling ncp 'office'

We have a look into the resolv.conf again. The nameserver should have switched to 192.168.1.43:

root@tachikoma:/home/jmoekamp# cat /etc/resolv.conf

#
# Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
#

#
# AUTOGENERATED_FROM_SMF_V1
#
# WARNING: THIS FILE GENERATED FROM SMF DATA.
#   DO NOT EDIT THIS FILE.  EDITS WILL BE LOST.
# See resolv.conf(4) for details.

domain  office.c0t0d0s0.org
nameserver      192.168.1.43

Nice.

Without that automatic stuff ....

Configuring all this stuff manually isn't hard as well. Perhaps you have chosen "Automatic" initially at install time in the CUI. So at first we have to get rid of the automatisms.

root@tachikoma:/home/jmoekamp# netadm enable -p ncp defaultfixed
Enabling ncp 'DefaultFixed'

Okay, now we configure an ip interface called net0 and assign an ip address

root@tachikoma:/home/jmoekamp# dladm show-phys
LINK              MEDIA                STATE      SPEED  DUPLEX    DEVICE
net0              Ethernet             unknown    0      unknown   pcn0
root@tachikoma:/home/jmoekamp# ipadm create-ip net0
root@tachikoma:/home/jmoekamp# ipadm create-addr -T static -a  192.168.1.28/24
net0/v4

Of course we need a defaultrouter. With this command we configure such a persistent default route.

root@tachikoma:/home/jmoekamp# route -p add default 192.168.1.1
add net default: gateway 192.168.1.1
add persistent net default: gateway 192.168.1.1

Configuring the dns server is a little bit more complex:

root@tachikoma:/home/jmoekamp# svccfg  -s "dns/client" setprop "config/nameserver = net_address: ( 192.168.1.1 )"
root@tachikoma:/home/jmoekamp# svccfg  -s "dns/client" setprop 'config/domain = astring: ("c0t0d0s0.org")'
root@tachikoma:/home/jmoekamp# svccfg -s "name-service/switch" setprop 'config/host = astring: "files dns"'
root@tachikoma:/home/jmoekamp# svcadm refresh name-service/switch
root@tachikoma:/home/jmoekamp# svcadm enable dns/client

Okay, let's check the result:

root@tachikoma:/home/jmoekamp# grep "192.168.1.43" /etc/resolv.conf
nameserver      192.168.1.43
root@tachikoma:/home/jmoekamp# grep "host" /etc/nsswitch.conf
hosts:  files dns

Everything works as designed.

Being relaxed in regard of retention

nospam@example.com (Joerg Moellenkamp) — Mon, 27 Feb 2012 21:16:15 +0100

Robin Harris of StorageMojo pointed to an interesting research paper: "Optimizing NAND Flash-Based SSDs via Retention Relaxation". The idea of the method described in that paper is basically: The physics behind the process of writing to NAND-flash allows you to write you faster, when you shorten the retention time. The shorter the retention time, the faster the write. Retention time? That the span of time you have to be capable to read the data from a device.

Obviously I mapped that automatically into the ZFS world: For an separated ZIL device write latency is a really, really important metric.However: The normal live time of the data writen to the sZIL? Just until the transaction group has been committed to the pool. A few seconds. However the need retention time is not that short, because you have address failures. You write something like a ZIL for a reason. In the case of a system failure the data has to survive at least as long until the same or a different system is able to commit the data - that wasn't commited before the failure - that is still on the sZIL to the pool devices. However how long is this? A day perhaps a week. But surely not the standard of 1year or 10 years. However the standard mechanism writes so it could be read for 1 or 10 years as mandated by some standard bodies. And this is exactly the margin the idea in the paper uses. The model in the paper suggest a write speedup of 2.5 in response time for a TPC-C-similar load (figure 13) when you target for a retention time of two weeks instead of a year.

When you combine sZIL and flash storage capable of such a relaxed retention you could basically use such an optimization for pretty much all data storage needs, as the data is still stored in the pool. Further more you can forget about the refreshment of the data as suggested by the paper for data with longer retention time needs, because by it's nature all data is really short-lived and other processes take care of making the data persistent for the next 10 years. And as a weird idea at the end: You could even use a retention-relaxed SSD as an sZIL device in front of a pool of SSD without relaxed retention.

Using encrypted lofi devices for backup

nospam@example.com (Joerg Moellenkamp) — Mon, 27 Feb 2012 16:26:14 +0100

My colleague Constantin wrote a nice article about using encrypted loopback file based pools for backup purposes for example. And don't forget you can do deduplication or snapshots as well for your backuped data. And in case you don't know how migrate your data into this files ... use shadow migration

More than this

nospam@example.com (Joerg Moellenkamp) — Sun, 26 Feb 2012 08:36:12 +0100

I had many interesting discussions in the last few days. However some of them gave me the impression that i should explain one thing. I want to use one example for it: A customer asked me while having some coffee at the Tech Days: "Zones? Isn't that just jails like in FreeBSD?". It's that old question, i get since the introduction of Zones. Just to make it clear: It's not a text in regard of FreeBSD. It's a text about the tendency of people just to pick a single feature and to say "Isn't that feature like ". But it isn't that easy.

I don't want to discuss about that question, if a feature is really like another. However i want to introduce a different tought into this:"A feature is not only a feature when you have an overarching architecture and an overarching idea where the architecture is heading to.It's an enabler. And a feature is often just the next question".

A feature is just the next question? Yes, that right. Because every feature you introduce is just the starting point for the next feature. When we introduced Zones years ago, we had a lot open questions not much later: How do you patch those zones? Especially when you have dozens of them? How to delegate administration? How do you install zones in a fast manner? How to implement bootenvironments, for the OS as well as the Zones? How do you reduce hard-to-find problems of an architecture that shares a kernel, but has several copied userlands? Questions, that have perhaps no technical background, but resulting in technical changes because of operational requirements. Perhaps, at the beginning Jails and Zones may have been similar concepts. But when you look today into the construct, Zones is a lot more. Zones is a large interdepending web of features inside of zones and outsides of zones to enable customers to work with them as efficient as possible.

However: Some of the challenges are just solvable when you have an overarching architecture and the power to decide on the architecture. And this is what i want to say with "a feature is not only a feature". Sometimes it's an enabler for a different feature. For example you have to be capable to say "ZFS is the only filesystem for booting and keeping zone roots" then you have a foundation you can use to implement other features. You can take all the mechanisms of ZFS for example for granted to base other features on it.

An example from the automobile sector? Ever asked why the automatic parking for a VW Golf is that cheap? Well, it just reuses an electro motor that it's there for power steering. You just need some software and a computer to give directly orders to this already existing power steering motor? When you allow all engineering teams to use it's own power steering implementing automatic parking in all vehicles is much more difficult.

Or in Solaris: Fast zone cloning? You need snapshots for it. So go to the ZFS people. Exclusive IP-Stack for a zone? You need a revamped IP stack for it. Ask the Crossbow people. Many things are severely depending on each other? Boot environments like in Solaris 11? Just feasible with a filesystem capable to do snapshots. IPS was invented to a part to have a packaging format that is much more aware of a concept like zones than just post/pre install scripts where zones was just an afterthought. Bandwidth Management? The Crossbow people again. Resource Management for your zones? You could use the foundation already laid out by the people with the Solaris Resource Manager years ago.

And there i'm at the point where i'm saying it doesn't suffice to have a feature, for example like Jails. At the introduction of a feature, a new journey just begins to solve all implication of a new feature. And you have to go all the way to make it really good.