Nowadays,several storage virtualization technologies are in use in order to enable better functionality and more advanced features within the storage system. RAID is such a powerful storage virtualization technology defined by David Patterson,Garth A Gibson,and Randy Katz at University of California,Berkeley in 1987.

This blog will make you walk through the various aspects of RAID.

RAID Defined

RAID is the acronym for “Redundant Array of Independent Disks”. RAID combines multiple small, independent disk drives into a single logical unit .This will yield performance exceeding that of one large, independent drive. Such logical units are commonly known as RAID arrays which appear to the computer as a single virtual drive.All the hard disks in RAID array will be accessed in parallel.

Why do we use RAID?

The need for RAID can be described in two points given below:

1,Overall increase in I/O performance: Array of disks accessed in parallel will give more data throughput than a single disk.

2,Provides data redundancy: Provides fault-tolerance by redundantly storing information in various ways.

RAID Implementations

There are two forms of implementation for RAID, hardware and software.

Software RAID:

Software RAID is part of OS,which works on partition level. It runs on the server’s CPU and is directly dependent on server CPU performance and load. It is more suitable for RAID 0 and RAID 1 setup.Its a low cost solution which makes it a perfect buddy for home and small business users. Since it occupies the host system memory and CPU cycles ,it may result in the degradation of server performance,which makes it least recommended for implementing higher order RAID levels which uses parity functions. Another drawback is that It does not support advanced RAID features like Hot Swapping(process of replacing the faulty hard disk without shutting down the server).

Hardware RAID:

It uses dedicated hardware RAID controller to manage the RAID array. Since It runs on Raid controllers CPU,there won’t be any overhead(CPU ,RAM etc). Host CPU can execute applications while the array adapter’s processor simultaneously executes array functions. Hardware RAID controllers interface with the system and hard drives through SCSI or IDE/ATA. RAID controllers can either be integrated with the system motherboard itself(Bus-Based or Controller Card Hardware RAID) or it can be an external dedicated hardware solution(Intelligent, External RAID Controller). Since it provides the highest performance possible,it can be used for mission critical applications.

RAID Levels:

Raid can be classified into six levels based on how the Raid Controller distribute the data in virtual hard disk to the physical disks. Six RAID levels are RAID-0 to RAID-5. Each RAID levels has different disk fault tolerance and trade-offs in features and performance. Among the different RAID levels,only RAID 0, 1, 3 and 5 are commonly used.
Apart from the above mentioned levels,certain combinations like RAID 10,RAID 01 etc are also possible.

RAID-0

Figure 1   RAID- 0 layout

Technique(s) used: Block Level Striping.

Explanation: In RAID 0,the data is broken into block sized units and it is striped across the hard disks. In this example, the first block of data, A0, is written to the first disk, the second block of data, A1, is written to the second disk, the third block of data, B0, is written to the first disk, and so on. Striping data across the disks means that the overall write performance of the disk set is very fast, usually much faster than a single disk. When a read request is received by the RAID controller,it reads both A0 and A1 at the same time since they are on separate disks,doubling the read performance relative to a single disk. Performance is very good but the failure of any one disk in the array results in data loss.

Minimum number of disks needed to setup a RAID-0 array is 2.

The capacity of RAID 0 can be calculated as:

Capacity = n * min(disk sizes)

where n = number of disks in the array.
min(disk sizes) = minimum common capacity across the drives.

Merits:

High I/O performance

De-merits:

No data redundancy.

RAID-1

Figure-2  RAID-1 layout

Technique(s) used : Mirroring

Explanation: It is the first real implementation of RAID which offers Redundancy. RAID 1 uses Mirroring technique to provide redundancy.RAID-1 takes an incoming block of data to one drive and creates a mirror image (copy) of it on a second drive.In this illustration when block A1 is written to disk 0, the same block is also written to disk 1. So the overall write performance of a RAID-1 array is the same as a single disk .The read performance is actually faster for a RAID-1 array relative to a single disk. If one of the drives fails, the other drive still has all the data that existed on the system. This provides a full level of redundancy for the data on the system.

Minimum number of disks needed to setup RAID-1 array is 2.

Storage capacity is only as large as the smallest drive. Capacity of the RAID-1 array can be calculated using

Capacity = min(disk sizes)

where,min(disk sizes) = minimum common capacity across the drives.

Merit:

Provides full redundancy of data and good read performance.

De-Merits:

Limited write performance.

RAID-2

Techniques used: Bit level striping+Hamming code error correction.

Explanation:The basic concept is that,RAID-2 stripes data at the bit level instead of the block level and uses a Hamming Coding for parity computations. In RAID 2,first bit is written on first disk,second bit is written to second disk and so on. Then Hamming Code is calculated for the bits and the resulting bit is stored on a separate disk. This level of RAID is intended for use in drives which do not have built-in error detection. If one of the disks fail the remaining bits of the byte and the associated ECC(Error Correction Codes) bits can be used to reconstruct the data.

RAID-2 is no longer really used,since the hard disks nowadays uses has built-in error correction techniques.

RAID-3

Figure 3  RAID-3 layout

Technique(s) used:Byte level striping + parity.

Explanation: It uses multiple data disks, and a dedicated disk to store parity.A chunk of data is split into bytes. Byte A0 is written to disk 0,byte A1 is written to disk 1,and byte A2 written to disk 2 and so on.Then the parity of bytes A0,A1 and A2 are computed and written to disk 3.Since parity is used, a RAID 3 can withstand a single disk failure without losing data or access to data.Parity is calculated using XOR Operation. A RAID-3 array tolerates the loss of any single drive. Data in the failed drive can be reconstructed by XOR ing the data bytes in the remaining drives in the array without much degradation in performance. Accessing a single block of data requires access to more than one hard disks,so that the spindles should be synchronized.

Minimum number of disks needed to setup RAID-3 array is 3. The three disks has to be identical.

Capacity of the RAID-3 array can be calculated using

Capacity = min(disk sizes) * (n-1)

where, n = number of disks in the array.
min(disk sizes) = minimum common capacity across the drives.

Merit:

1)RAID-3 provides high throughput (both read and write) for large data transfers
2) Disk failures do not significantly slow down throughput.

De-merit:

1) Cannot be implemented using software RAID since it is more resource intensive.
2) Performance is slower for small I/O operations                                                                      3) Controller design is fairly complex.

RAID-4

Figure-4 RAID-4 layout

Technique(s) used: Block level striping +Parity

Description: RAID 4 is quite similar to that of RAID 3. It also uses a dedicated parity disk, but the difference is that, it stripes the data at block level. A chunk of data is splitted into blocks. Block A0 is written to Disk-0,A1 is written to Disk-1 and A2 is written to Disk-2 and so on. The parity of the blocks(Ap) are calculated and stored in the dedicated parity disk. Since the data is striped at the block level ,hard disks can be accessed independently during data read/write. It can tolerate the loss of one drive

Minimum number of disks needed to setup RAID-4 array is 3(Two disks for storing the data and third one for storing parity information) . All the disks should be identical.

Capacity of RAID-4 array can be calculated using:

Capacity = min(disk sizes) * (n-1)

where n = number of disks in the array.
min(disk sizes) = minimum common capacity across the drives.

Merits:

1) Unlike RAID 3, it does not require synchronized spindles.                                                     2) Good read performance since all of the drives are read at the same time.

De-merits:

Write performance is not that good because of the bottleneck of the parity drive.

RAID-5

Figure:5 RAID 5 layout

Technologies used:Striping+Distributed parity

Description: This is the most popular RAID level.It uses block level striping and parity is distributed across all the drives in the array. It offers higher performance than level 1-4.It also provides high storage capacity. Here parity information will also be stored along with the data disks.

Minimum number of disks needed is 3(two disks for storing data and the third one for storing parity information.). All the 3 disks should be identical.

Capacity of the RAID-5 array can be calculated using

Capacity = min(disk sizes) * (n-1)

where n =  number of disks in the array.
min(disk sizes) =  minimum common capacity across the drives.

Merits:

1) Good data redundancy/availability (can tolerate the lose of 1 drive)
2) Very good read performance since all of the drives can be read at the same time.

De-merits:

1) Write performance is adequate (better than RAID-4).
2) Write performance for small I/O is poor.

Conclusion

RAID is a good solution for those who need more transfer performance, redundancy, and storage capacity in their data storage systems. I hope you’ve enjoyed reading this article and maybe even learned more about RAID.

Since prefork have a one process per thread structure it can provide isolation among different connections. So we can say that it is more secure at the cost of more RAM and CPU power. Worker MPM needs less RAM and CPU power but does not provide same level of request-to-request isolation as a process-based MPM does.Now let us look in to the prefork MPM tuning which is more common MPM than worker.

Prefork Directives

Example for prefork directives

StartServers 8
MinSpareServers 5
MaxSpareServers 10
MaxClients 30
MaxRequestsPerChild 500

StartServers : Number of apache child processes generated during the apache startup.

MinSpareServers: Spare servers are child processes in idle(not handling any requests). If the total idle processes are less than
MinSpareServers directive then apache parent process will create child processes up to MinSpareServers .

MaxSpareServers: If the total idle child processes is more than this directive , then parent pocess will kill additional idle processes.

MaxClients: This is the most important MPM directive for tuning apache performance.Parent process will dynamically spawn new child processes as the incoming request raises. MaxClients is the maximum child processes created for handling requests or in other words it is the max simultaneous requests apache can handle. This value should be optimal. If it is too low apache can only handle few requests and excess requests will be queued and it may get timed out.If it is too high server will begin to swap and it seriously affects entire server performance.

MaxRequestsPerChild: After handling this much requests child process will die .MaxRequestsPerChild is the requests that a child process will handle in its life time.If it is too low in a busy server, apache will utilize a good CPU power for killing and spawning new child processes which may cause more CPU burden. But at the same time it is always good to recycle it in a timely manner, otherwise it may cause common issues like memory leak , process bloat etc.

How to set MaxClients.

Before choosing a value we need to analyze the server , i.e check the RAM size and applications running other than apache like mysql , java applications etc. Then roughly calculate the memory dedicated for those applications . For example ,we might have defined innodb buffer spool size for mysql and java heap size for java applications . Substract that much memory from total RAM size. Suppose you have 2 GB RAM and 500 MB allocated for mysql(it depends on your DB size) and 250 for java and reserved some memory for system applications ,in this setup we can reserve memory up to 1 GB for apache . On next step we need to calculate avereage process memory usage for apache. For calculating it , during the peak traffic time run the following command

ps aux| awk ‘/apach[e]/{total+=$6}END{print total}’ this calculates total physical memory used by all apache process , to calculate average memory usage ,devide above value with total apache processes .
Finally we can optimize MaxClients value by deviding memory reserved for apache (1G) by process’s average memory usage. (Lets imagine its 35M here) .

MaxClients <= 1G/35 M = 30. We can reduce avg memory usage by removing unwanted apache modules and using php cache like PHP op-code cache/accelerator .If serever have good traffic, then fix the MaxRequestsPerChild deirective some higher values like 2000. Thoroughly observe server for some days after tuning , some time you need to tweak it 2 – 3 times for getting the best result. Good Luck!

• Inventory your systems (hardware and software information)
• Install and update software on your systems
• Collect and distribute your custom software packages into manageable groups
• Provision (kickstart) your systems
• Manage and deploy configuration files to your systems
• Monitor your systems
• Provision virtual guests
• Start/stop/configure virtual guests
• Distribute content across multiple geographical sites in an efficient manner

It  manages software content updates for Red Hat derived distributions such as Fedora, CentOS, and Scientific Linux, within your firewall. Limited support for Debian is also available. Spacewalk allows administrators to efficiently manage the systems on their network. Through a simple user interface, administrators can perform patch management, updates, monitoring, and maintenance. And because Spacewalk is Web-based, it can be accessed from anywhere. Spacewalk or Proxy server options provide advanced capabilities and the ability to get updates directly from Red Hat with even greater levels of security and reduced network bandwidth. As I mentioned already spacewalk is the upstream project of Redhat Network Satellite (RHN). The Changes will occur frequenty in the Spacewalk project to fulfill this mission of having the latest technology. However, if your needs require stability and support over access to the latest management technology, you may decide that a Satellite subscription is right for you.

Creating Channels

1. Create a base channel within Spacewalk.

Channels > Manage Software Channels > Create New Channel

2. Fill up all the required fields such as Channel Name, Channel Label, and Channel Summary

3. Select the Parent (its depends upon your channel)

4. Select the channel architecture from the drop down list

5. Select the Checksum type

6. Write a description about your channel

7. Fill the Contact support information, Channel access control and security GPG

8. Now click the “Create Channel” button.

The channel with the specified name has been created.

Creating activation key

Activation keys are used to register a system to spacewalk server. System registered with an activation key will inherit the characteristics defined by that key.

1. To create an activation key

Systems > Activation keys > Create new key

2. Enter the description of the activation key

3. If you have a specific key value, type it in the key textbox else leave it as blank. Spacewalk will generate a key after clicking create key button.

4. Enter a numeric value for the limited usage of the key. In case if you want to use the key unlimited times leave the usage textbox as blank.

5. Select the base channel from the drop down list box or choose “Spacewalk Default” to allow systems to register to the default Red Hat provided channel that corresponds to their installed version of Red Hat Enterprise Linux.

6. Enable the universal default check box and click “Create Activation Key”

Registering Clients

Install the client-tools in the client

For RHEL 5 / CentOS 5

# rpm -Uvh http://spacewalk.redhat.com/yum/1.7/RHEL/5/i386/spacewalk-client-repo-1.7-5.el5.noarch.rpm

For CentOS 6

# rpm -Uvh http://spacewalk.redhat.com/yum/1.7/RHEL/6/i386/spacewalk-client-repo-1.7-5.el6.noarch.rpm

To register the client host, you need to install the client registration tools. But those tools are not avail in the redhat repository. You can found those packages in EPEL repository

For RHEL 5 / CebtOS 5

# BASEARCH=$(uname -i)# rpm -Uvh http://dl.fedoraproject.org/pub/epel/5/$BASEARCH/epel-release-5-4.noarch.rpm

For CentOS 6

# BASEARCH=$(uname -i)# rpm -Uvh http://dl.fedoraproject.org/pub/epel/6/$BASEARCH/epel-release-6-5.noarch.rpm

Now install the client packages

# yum install rhn-client-tools rhn-check rhn-setup rhnsd m2crypto yum-rhn-plugin

Register your CentOS or Red Hat Enterprise Linux system to Spacewalk using the activation key you created earlier

# rhnreg_ks --serverUrl=http://YourSpacewalk.example.org/XMLRPC --activationkey=<key-with-rhel-custom-channel>

rhnreg_ks is used for registration of clients to Spacewalk. If you need to re-register a client to your Spacewalk server or change registration from one environment or server to another Spacewalk server then use the “–force” flag with rhnreg_ks, otherwise there is no need to use “–force”.

Adding packages to repository

There are two ways to add packages to the spacewalk server. We can either add using spacewalk-repo-sync or rhnpush command.

Spacewalk-repo-sync

The  spacewalk-repo-sync tool is used to sync packages from external or local yum repositories. All the packages within the specified repository will be added to the channel.Any url supported by yum is supported by this utility, including mirror lists.  If the url is not supplied, the tool will look to see what  repositories are associated with the specified channel and use those.

Example

spacewalk-repo-sync --channel=repo1 --url=http://example.com/yum-repo/
spacewalk-repo-sync --channel=repo2 --url=file:///var/share/localrepo/
spacewalk-repo-sync --channel=repom --url=http://example.com/mirrorlist.xml/

You can also use WebGUI and this is the easiest way to create repositories

• Goto Channels -> Manage Software Channels -> Manage Repositories -> create new repository

After creating the repository, you need to link it to one or more Software Channels.

• Goto: Channels -> Manage Software Channels -> Choose the channel to be linked -> Repositories -> Select the repositories to be linked to the channel -> Update Repositories.

Now you can sync the repository by clicking on the sync tab.

Click on sync now or schedule a sync.

RHNpush

The  RHN  Satellite Package Pusher (rhnpush) pushes RPMs into locally managed channels on an RHN Satellite Server. Rhnpush has three configuration files called /etc/sysconfig/rhn/rhnpushrc, ~/.rhnpushrc, and ./.rhnpushrc.

/etc/sysconfig/rhn/rhnpushrc is the system-wide default settings for rhnpush.
~/.rhnpushrc is the user-specific settings that override the system-wide settings.
./.rhnpushrc controls the directory specific settings that override the user-specific and system-specific settings.

/etc/sysconfig/rhn/rhnpushrc must be present for rhnpush to function correctly. If it is missing, rhnpush will attempt to use a series of  default  settings  stored  internally as a replacement. ~/.rhnpushrc and ./.rhnpushrc are not required to be present, but will be used if they are present. They are not created automatically by rhnpush.

Rhnpush uses a cache, stored at ~/.rhnpushcache, to temporarily hold the username and password for a user. If the cache is missing, it will be created by rhnpush.
If the cache is present and not too old, the usename-password combo will be used as a convenience for the user. The amount of time a cache lasts is configurable in any of the three configuration files. If your username/password combination gets messed up you have two options. One, you can wait until the cache expires, which takes  minutes  by  default. Two, you can use the –new_cache option to force rhnpush to let you reenter your username/password.

Using  the  –stdin  and –dir options at the same time works as follows: rhnpush will let you type in rpm names, each rpm name on a separate line. When       you have finished entering in rpm names, hit Ctrl-D. Rhnpush will then grab the files from directory you specified with –dir, put them in a  list  with       the rpms you listed through standard input, and send them to the channel that was listed on the command-line or in the configuration files.

Note : Make sure /var/satellite exists on the Spacewalk server and has owner:group apache before pushing.

[root@sathishhost ~]# chgrp apache /var/satellite/ -R

[root@sathishhost ~]# ls -l /var | grep satellite

drwxr-xr-x.  3 apache apache 4096 Mar 20 10:06 satellite

Example

rhnpush --server localhost -u <username> -p <password> --channel <channel-name> /usr/local/src/additional/*.rpm


rhnpush --server localhost -u sathish -p redhat --channel spacewalk-nightly-rhel-6-x86_64 /usr/local/src/additional/*.rpm


rhnpush -v --channel=<channel-name> --server=http://localhost/APP --dir=<package-dir>


rhnpush -v --channel=spacewalk-nightly-rhel-6-x86_64 --server=http://localhost/APP --dir=/usr/local/src/additional

Thanks to Dancer, i just deployed a Music Web App – “Spark Impulse” in our office.

What is Dancer ?

Dancer is a simple but powerful web application framework in Perl. Dancer stole the approach from Sinatra, a web framework for Ruby. Yes, The bad artists imitate, The great artists steal !!

Why Dancer ?

• LightWeight
• StandAlone
• PSGI/Plack Compliant
• Expressive Syntax
• Few Dependencies
• Few Configuration Steps

Installation

Using cpanminus

spark$ curl -L http://cpanmin.us | perl - --sudo Dancer

Using cpan shell

spark$ perl -MCPAN -e shell

cpan shell -- CPAN exploration and modules installation (v1.9402)
Enter 'h' for help.

cpan[1]> install Dancer


Or even by hand

spark$ wget http://search.cpan.org/CPAN/authors/id/X/XS/XSAWYERX/Dancer-1.3095.tar.gz
spark$ tar -zxf Dancer-1.3095.tar.gz
spark$ cd Dancer-1.3095
spark$ perl Makefile.PL
spark$ make
spark$ make test
spark$ make install


A Dancer script itself is a webserver. Yes, you read it correctly – run the script from command prompt and your web application will spring into existance.

spark$ ./myapp.pl
>> Dancer 1.3092 server 9194 listening on http://0.0.0.0:3000
>> Dancer::Plugin::Database (1.81)
>> Dancer::Plugin::Database::Handle (0.12)
== Entering the development dance floor ...

With the following code in your myapp.pl script you say a big hello to the world at http://:3000/

#!/usr/bin/env perl
use Dancer;
get '/' => sub {
"Hello World !"
};
dance;

Dancer app is defined with route handlers. A route handler is basically a ‘sub’ ( function ) associated to an HTTP method and a path pattern. Valid HTTP methods are GET, POST, PUT, DELETE. But usually it will either be a GET or a POST !

Path Patterns includes Named Matching, WildCards Matching, Regex Matching, Conditional Matching as shown below. A route pattern can also contain one or more tokens (a word prefixed with ‘:’).

get '/hello/:name' => sub {
"Hi" . param('name') . ", Welcome here!";
}

When you access http://localhost:3000/hello/Peter, server should respond with a page – Hi Peter, Welcome here!

To make the token optional suffix it with a “?”

get '/hello/:name?' => sub {
"Hello there " . (param('name') || "whoever you are!");
};

You may use regex patterns for defining routes. And Dancer will return the matches in an arrayref, accessible via the keyword ‘splat’.

get '/download/*.*' => sub {
my ($file, $ext) = splat;
# do something with $file.$ext here
};

get qr{/hello/([\w]+)} => sub {
my ($name) = splat;
return "Hello $name";
}

So processing a HTTP request is equal to finding a matching route handler. When a request matches with a route handler, dancer executes that route handler.

Enough to start with !

I’m planning to add more blogs under the same topic. Till then, make some simple moves and start dancing !!

At the outset of 2012 India has already acclaimed as the best country to provide IT related services. There are enough brands to prove this claim, Wipro, Infosys, TCS etc. West already knows these companies can give a huge traction to their business if they engage with these companies, but what about smaller players who wants to run their online business and their budgets are limited to few thousands dollars. Its obvious that they can’t approach these big companies and its hard for them to identify trust-able small players either, who can provide quality service for their business.

Companies like SparkSupport fill this gap. So what should be the ideal checklist for a businessman who wants to engage with an offshore business partner. Its easy to get the websites of the companies providing the services of his requirement and now he should start communicating with them. From the initial conversation he should get a basic picture of the company structure.

In India a Private Limited Company will give you an authenticity that company is existing. Try to avoid Partnership or Proprietorship they will have no liabilities and they can shut down any day. Only people who are serious about their business will register as a Private Limited Company.

Always start with a pilot project. You can gauge the following qualities in the pilot project.

Trust

As the word denotes you should be filled with confidence that this company deliver what they have promised. If you have given only a part of the major project, by now you should be able to analyse how good is the team to handle the whole project.

Reporting

You would have chosen either hourly billing or dedicated staff for the project you have outsourced. Whatever be the case to know the project status you shouldn’t call them up, if the company has got a process they would intimate you with daily updates what all things completed and what all left. If the company provides this without asserting upon this point, then you can assume this company is worth.

Communication

In any projects communication is really important. Requirements are susceptible to changes and you might have identified some drastic changes which you want in the project. Its not easy for you to communicate this to your team as they will come up with lot of arguments to block your desire. But you should understand you are the business man and you know the real game of making money better than anyone else. You know when, where and how to spend your money on something and you know how to reap money out of it. But its very difficult for the developers or coders to understand and they are the least educated about running a business. These situations makes it really hard for you  though you are ready to revise your budget to make it happen. So the point here is you should have other people  who are in the management of the company with whom you can talk to and who understands you better than the coders.

Diverse Skill-set

The company you choose should have a diverse portfolio. It won’t be easier for you to run around different companies to complete a project. Moreover signing NDA , SLA with all these companies will be cumbersome. If the chosen company has diverse skill set other than coding then it will be much convenient for you in completing the project. Take the scenario that you have decided to build an online webstore. Other then coding the project requires,  a hosting space to host the site,  a team to help you with the deployment, a team to design your store , an advanced team if you decide to host it in a cloud environment etc. So always look out for companies who can provide you all this.

By the above points you can now weed out the incompetent ones and choose the best company with whom you can build a strong relationship which lasts forever.

Reach out to me if you need any assistance info[@]sparksupport.com

Microsoft Hyper-V, codenamed Viridian and formerly known as Windows Server Virtualization, is a hypervisor-based virtualization system for x86-64 systems. Hyper-V exists in two variants: as a stand-alone product called Microsoft Hyper-V Server 2008, and as an installable role in Windows Server 2008 R2 and Windows Server 2008 (the former containing the later release of Hyper-V).

Hyper-V on a Familiar Operating System

Unlike some other server virtualization systems that are hosted on the Linux operating system (VMware ESX) or proprietary host systems, Hyper-V runs right on a familiar Microsoft Windows Server operating system. Network administrators do not need to learn a new operating system, management system, or specialized tools. Early adopters of Hyper-V, even without documentation or training, have been able to install the Hyper-V server role, finding it just like installing any other server role (such as installing domain name service [DNS], media services, Internet Information Services [IIS] web services, and the like). The administrative tools for Hyper-V are also just like any other administrative tool in Windows. Therefore, the creation of virtual guest sessions, the monitoring of those sessions, and the administration of guest sessions is a familiar process for IT administrators. The ease of learning, using, and supporting Hyper-V has been a huge factor in organizations adopting Hyper-V for their virtual server environments.

Hyper-V Support More Than Just Windows Guest Sessions

With the release of Hyper-V, Microsoft made a concerted effort to ensure that Hyper-V not only supports Windows guest sessions (like Windows 2003 and Windows 2008), but also non-Windows guest sessions running Linux. By providing support for a variety of guest sessions, Microsoft is enabling organizations to consolidate both their Windows and non- Windows server systems onto fewer Hyper-V host servers.

NOTE

Hyper-V in Windows 2008 is supported only on x64-bit systems that have hardware assisted virtualization support. Therefore, an organization cannot load up the 32-bit version of Windows 2008 and try to set up virtual guest sessions on the 32-bit host version of Windows.

These are the settings and changes that need to be made prior to installing the Hyper-V role on your machine:

1. Make the necessary BIOS changes.
2. Install Windows Updates
3. Change the default Host Name.
4. Configure the host’s product key and activate it.
5. Change the IP to static addresses.
6. Enabled RDP support.
7. Join the host to a domain.
8. Configure Remote Management.
9. Enable remote disk management.

1. BIOS changes

You must enter the BIOS setup of the server and make sure that “Virtualization Technology” and “Execute Disable” are both set to Enabled.  In most cases, the required BIOS settings can be found in these BIOS sections (actual names may differ, based upon your server’s BIOS settings.

• Security > Execute Disable (set to On)
• Performance > Virtualization (set to On)
• Performance > VT for Direct I/O Access (set to On)
• Performance > Trusted Execution (set to Off)

2. Install Windows Updates

By default, a Windows Server 2008/R2 machine will receive IP address and other settings automatically from a DHCP (if there is one).With these settings, in most cases, it will be possible for you to access the Internet. If that is correct, one of your first tasks would need to be installing all critical Windows Updates.

This can be done through several methods including the UI and the command line, but in this article I’ll describe the most common method – through the UI.

Use one of the following methods:

Open Server Manager – Click “Configure Updates”.

In Initial Configuration Tasks – Click “Download and install updates”.

On the Start menu – type “Update”, then click “Windows Update”.

You will need to reboot the server once the updates were installed.

3. Host name

By default, a Windows Server 2008/R2 machine will receive an automatically-generated host name. In most cases, we will want to change this host name to something more meaningful to us.

It is possible to change the host name through several methods including the UI and the command line (the NETDOM command), but in this article I’ll describe the most common method – through the UI.

Use one of the following methods:

Open Server Manager – Click “Change System Properties”.

In Initial Configuration Tasks – Click “Provide computer name and domain”.

On the Computer icon – right-click and select “Properties”, then click “Change Settings”.

Enter a descriptive computer name (try to limit it to 15 characters if possible) and click “Ok”.

You will need to reboot the machine in order to continue.

4. Product key and activation

Not required if server will be used for a short-period testing, however, in a production environment, you must activate the server.

Unlike older OSs, Windows Server 2008 R2 does not ask you for the product key during the setup. You need to provide it after the setup has completed.

To enter the product ID you can use the UI or the command line (using SLMGR.VBS command, which is useful for Server Core and remote installations). I will use the UI in this example.

Use one of the following methods:

Open Server Manager – Click “Activate Windows”.

In Initial Configuration Tasks – Click “Activate Windows”.

On the Computer icon – right-click and select “Properties”, then click “Activate Windows”.

Enter the correct product key and click on “Next”.

5. Static TCP/IP settings

By default, a Windows Server 2008/R2 machine will receive IP address and other settings automatically. To add the server to a domain and to access it remotely you need to properly configure an IP address, Subnet Mask, Default Gateway and DNS Server IP. These can be configured through DHCP, but since this is a server, you’d probably want to manually configure them.

To do so, you can use the UI or the command line (the NETSH command). I will use the UI in this example.

Use one of the following methods:

Open Server Manager – Click “View Network Connections”.

In Initial Configuration Tasks – Click “Configure Networking”.

On the tray area – right-click the network icon and select “Open Network and Sharing Center”, then click “Change adapter settings”.

On the Start menu, type “ncpa.cpl” and press “Enter”.

In the Network Connections window, right-click the network adapter(s) that’s connected to the network and select “Properties”.

Click to select “Internet Protocol Version 4 (TCP/IPv4)” and click on “Properties”.

Type in the assigned IP address, Subnet Mask, Default Gateway, and DNS settings.

Note that you will need to make sure you properly configure the host’s DNS settings in order to add it to a domain.

6. Enabled RDP support

Once the server has an IP address it’s most likely you’ll want to continue the configuration work remotely. To do so, we need to enable Remote Desktop.

Use one of the following methods:

Open Server Manager – Click “Configure Remote Desktop”.

In Initial Configuration Tasks – Click “Enable Remote Desktop”.

On the Computer icon – right-click and select “Properties”, then click “Remote Settings”.

7. Join the host to a domain

Hyper-V hosts are best managed if they’re a member of a domain. Domain membership is also required for other tasks that you might want to perform in the future (such as SCVMM 2008 R2 installation and others).

Like name changing, it is possible to add the host to a domain through several methods including the UI and the command line (the NETDOM command), but in this article I’ll describe the most common method – through the UI.

Use one of the following methods:

Open Server Manager – Click “Change System Properties”.

In Initial Configuration Tasks – Click “Provide computer name and domain”.

On the Computer icon – right-click and select “Properties”, then click “Change Settings”.

Enter the domain name and click “Ok”.

You will be asked to type your user name and password for the domain.

Once you are successfully joined to the domain, you will be prompted to restart your computer. You must restart your computer before the changes take effect.

8. Configure Remote Management

Remote Desktop is ok, but sometimes you do not need a full desktop to make a change or two, and you can use Server Manager or any other type of remote-connection MMC-snap-in (Note that in Windows Server 2008 R2, Server Manager can finally be used remotely).

To do so, open Server Manager – Click “Configure Server Manager Remote Management”.

To let this computer to be managed remotely by using Server Manager, select “Enable remote management of this server from other computers”. Click “Ok”.

9. Enable remote disks management

This should be done in order to allow you to remotely connect to the host’s disk subsystem and manage it. In order to connect to the disk subsystem remotely you need to set the Virtual Disk Service (VDS) to Automatic, and start it. Then you need to enable the remote-volume-management firewall exception.

To do so, follow these steps:

Open a Command Prompt window and type the following command:

sc config vds start= auto

Next, type:

net start vds

Next, type the following command to enable the remote-volume-management firewall exceptions:

netsh advfirewall firewall set rule group=”Remote Volume Management” new enable=yes

Very important note: Although this may not seem logical, you MUST also enable the same firewall exceptions on the machine you’re connecting FROM!!! Otherwise, you’ll get a “RPC Service Unavailable” message when you attempt to connect to the server’s disk subsystem remotely.

To install Hyper-V on Windows Server 2008 R2 you can use one of the following approaches. Note that all methods require a reboot after completion.

Method #1 – Through the GUI

Probably the easiest for this specific role. I would use this method.

1. Open Server Manager, wait for it to load.

2. Click on “Roles”, wait for it to load.

3. On the “Before you begin” page, click “Next”.

4. In the “Select Server Roles” page, click to select the Hyper-V role. Click “Next”.

5. Click “Next”.

6. Select all the Network Interface Cards (NICs) that you wish to assign for the Virtual Machines. Make sure you leave one NIC un-selected for host management. If you only have one NIC, select it, but make a note that it is best to have at least 2 NICS – one for the host and one for the VMs. These settings can be changed later.

7. In the “Confirm Installation Selections” page click “Install”.

8. Once finished, you will need to reboot the server. Click on the “Close” button, and then click “Yes” when you are prompted to reboot the server.

9. When the server reboots, log back into the server and the Server Manager should automatically load and resume the installation process.

After about a minute, you should see a message telling you that Hyper-V has installed successfully. Click “Close” to complete the wizard.

Note: Make sure you do not forget to enable the CPU Virtualization Mode and the Execute Disable bit as mentioned in prepare windows server 2008R2 for Hyper V role blog. If you fail to do so, you will receive an error when attempting to start a VM.

Method #2 – Using the Command Prompt

Using the servermanagercmd.exe command is easy, and only requires 3 words… A reboot is required at the end of the installation (which can also be added to the command, making it 4 words…). However, Hyper-V network connections will need to be changed after the installation.

1. Open a Command Prompt window with elevated permissions.

2. Type:

servermanagercmd -i Hype-V

If you want to automatically reboot the server when the installation is finished, type:

servermanagercmd -i Hyper-V -restart

Easy and simple. This is probably why Microsoft decided to deprecate the usage of servermanagercmd.exe.

Method #3 – Using PowerShell

In Windows Server 2008 R2, PowerShell is installed by default. However, in order to install roles with it, you need to import the Server Manager module.

1. Open a PowerShell window and type:

Import-Module servermanager

2. Once imported, type:

Add-WindowsFeature Hyper-V

If you want to automatically reboot the server when the installation is finished, type:

Add-WindowsFeature Hyper-V -restart

Easy and simple, but here too, Hyper-V network connections will need to be changed after the installation.

To open Hyper-V, click on Start > Administrative Tools > Hyper-V Manager

The first time you open Hyper-V, an End User license Agreement (EULA) page will open, take a moment to read it and then enable the checkbox beside I have read and agree to the terms of this EULA, then click on the Accept button. If you clicked on the Cancel button, then you will not be able to connect to any server running Hyper-V until you accept the EULA, which will keep popping up whenever you open Hyper-V or even try to connect to a server that has the Hyper-V role installed on.

The Hyper-V Manager console will open

From the right side pane, under Actions, click on Connect to Server . Hyper-V is installed locally on the machine you are working with, so keep the default selection on Local Computer (the computer this console is running on) and then click on OK.

The server name will be displayed in the left side pane, and now we have more Actions to select from the right side pane

To Create a new virtual machine, From the right side pane, click on New > Virtual Machine

On the Before You Begin page, click Next

On the Specify Name and Location page, type a meaningful name for your Virtual Machine, as for the location where the virtual machine will be stored, either keep the default location as shown, or change it to another path and then Click Next.

On the Assign Memory page, specify the amount of memory to allocate to this virtual machine. This depends on how much memory is installed on your system. Either keep the default displayed memory, or increase it. As I’m going to install Windows Server 2008, I am going to set the memory to be 2 GB. Click Next

Select a Virtual Network from the drop down list on the Configure Networking page. You can keep the virtual machine disconnected by not selecting any Virtual Network, Click Next

For Every Virtual Machine, you will need to connect it to a Virtual Hard Disk, on the Connect Virtual Hard Disk page, we will need to create a new virtual hard disk, as we do not have any existing virtual hard disk ( you can use existing virtual hard disk if you already have created virtual hard disk before , or if you have downloaded a virtual hard disk from Microsoft site )

On the Installation Options page,  you have multiple options to choose from where you are going to install the operating system, or you can even postpone this operation by choosing Install an operating system later. Insert the Windows Server 2008 DVD inside the DVD Drive, and select to install an operating system from a boot CD/DVD-ROM, if you have multiple DVD Drives, make sure to select the one which has the Windows Server 2008 DVD into it. Click Next

On the Completing the New Virtual Machine Wizard, take a moment to review your selections and then click Finish. If you need the virtual machine to be automatically started after it is created, then select the checkbox Start the Virtual Machine after it is created

Windows Server 2008 files will start to load

Select the language to install, Time and currency format and the keyboard language, and then click Next

Click on Install Now

Enter the product key, and keep the checkbox Automatically activate Windows when I’m online to activate your Windows copy when you are online, if you wish not to activate it, as this might be a test lab on your Hyper-V, then deselect this option and then click Next

Accept the license terms and click Next

Click Custom (advanced), on the Type of installation page

Select the drive / partition you want to install Windows Server 2008 on it and then click Next.
If you want to divide the virtual hard disk into two partitions, you can do this by selecting the drive , and then clicking on the Drive options (advanced) option

To divide the drive into different partitions, click on the New option, enter the new partition size, then click on the Apply button

Once you are done with creating the partitions, select the one that you want to install Windows Server 2008 on it, and then click on Next

Installation will start

The machine will reboot several times until the installation is completed.

One last note, in step # 10 , if you did not select to start the virtual machine after it is created, then to start and connect to the virtual machine, right click on the Virtual machine name inside Hyper-V Manager and click on Start, this will turn on the Virtual machine

Then right click on the Virtual machine name and click Connect, this will open the Virtual machine window.

Summary:

This article,shows you how to use Hyper-V Manager to create your first Virtual Machine, and then to install Windows Server 2008 as a guest operating system.  Start using a virtualized computing environment to improve the efficiency of your computing resources by utilizing more of your hardware resources. Enjoy Hyper-V !

Performing a Virtual to Virtual Migration of Guest Images

A strategy for migrating older images to Hyper-V is to do a virtual to virtual image migration.Via VMM, an administrator can select a running virtual machine (running VMware,XenServer, Virtual Server 2005, or the like) and choose to migrate the image to Hyper-V. This process extracts all the pertinent server image information, applications, data,Registry settings, user settings, and the like and moves the information over to a target Hyper-V host server. Once migrated, the Hyper-V integration tools can be installed, andthe image is now clear and ready to be supported by Hyper-V or VMM.

Following are the steps to convert a VMWare VM to Hyper-V VM

1. First you need to uninstall the VM tools from your VM
   
2. Then shutdown the VM
   
3. After that add a new IDE disk drive to your VM.
   
4. You need to boot up your virtual machine with both of the drives that is connected and check that it detects your new IDE drive. You can see the new drive as “not initialized” in Disk Management.
   
5. Then power off the virtual machine and remove the newly created IDE disk from the VM. Do not power on VMware Machine again.
   
6. Now you need to convert your VMDK file to VHD format by using the newest Vmdk2Vhd utility.
   
7. After that you can now uninstall the VMware Server and then install Hyper-V + on the current Windows Updates on your host server
   
8. Then create a new Virtual Machine in the Hyper-V.
   
9. On the Power and Install the “Integration Services” and reboot when prompted
   
10. Assign the original IP address to the new network card.
    
11. Then you can check the device manager
    
12. Then reboot
    
13. After that check all your applications and services are running
    
14. Finally done.
    

Note: If you have Win2008 VM’s then it’s not necessary to add a temporary IDE disk during migration but you might want to copy the relevant KB949219 (http://support.microsoft.com/kb/949219) update package to your VM before converting it. Otherwise it will start up with three warnings in the Device Manager for “Microsoft VMBus Video Device”, “Microsoft VMBus HID Miniport” and “Microsoft VMBus Network Adapter” – hence you will have no network access

Converting Vmware files to Hyper-V-compatible files by using VMDK to VHD converter tool:

Open the VMDK file, as shown below

Once the file is open, select a destination for the new VHD file and provide a file name.

Select destination and name VHD file. Click to start Conversion.

The above mentioned method is for converting guest operating systems in VMWARE to HYPER-V. The guest operating systems can be both windows and Linux based systems.