Running dstat normally gives you something like this :

# dstat --nocolor
----total-cpu-usage---- -dsk/total- -net/total- ---paging-- ---system--
usr sys idl wai hiq siq| read  writ| recv  send|  in   out | int   csw
  3   0  97   0   0   0| 820k  456k|   0     0 | 800B  866B|1054   255

And you can split the disk metrics up based on devices using something like this :

# dstat -D sda,sdb,total --nocolor
----total-cpu-usage---- --dsk/sda-- --dsk/sdb-- -dsk/total- -net/total- ---paging-- ---system--
usr sys idl wai hiq siq| read  writ: read  writ: read  writ| recv  send|  in   out | int   csw
  1   1  97   0   0   0| 176k   77k:  30k  162k: 411k  478k|   0     0 |3608B 4005B|1447  1458
 33   2  63   0   1   2|   0     0 :   0   216k:   0   432k|2470k 1611k|   0     0 |2915  6967
 31   2  65   0   1   1|   0     0 :   0     0 :   0     0 |2210k 1338k|   0     0 |2866  6051

But you can also get deeper level device names / nodes to measure – which is required in many cases if you have drivers for storage creating nodes further down the tree than /dev. Eg. I have a setup where there are four mysql instances running, each with its own dedicated storage :

# mount | grep srv
/dev/cciss/c0d1 on /var/lib/mysql/node1 type ext3 (rw)
/dev/cciss/c0d2 on /var/lib/mysql/node2 type ext3 (rw)
/dev/cciss/c0d3 on /var/lib/mysql/node3 type ext3 (rw)
/dev/cciss/c0d4 on /var/lib/mysql/node4 type ext3 (rw)
/dev/cciss/c0d5 on /srv/wal type ext3 (rw)

so in this case, to get dstat reporting working you need to mention just the component level, like this :

# dstat -D cciss/c0d1,cciss/c0d2,cciss/c0d3 --nocolor
----total-cpu-usage---- dsk/cciss/c dsk/cciss/c dsk/cciss/c -net/total- ---paging-- ---system--
usr sys idl wai hiq siq| read  writ: read  writ: read  writ| recv  send|  in   out | int   csw
  3   0  97   0   0   0| 209k   89k: 201k   86k: 204k   85k|   0     0 | 799B  865B|1055   256
 90   1   8   1   0   0|3196k   68k: 764k    0 : 816k   24k|1067k 1650k|   0     0 |1999   609
 95   1   3   1   0   0|2548k    0 :   0  4084k:2448k 5700k| 660k  791k|   0     0 |1611   571
 96   1   2   1   0   0|2628k    0 : 808k    0 :1620k    0 | 352k  798k|   0     0 |1835  1605

And you get the details, for each block device.

WARNING: Could not open 'kernel/net/netfilter/x_tables.ko': No such file or directory
FATAL: Could not open 'kernel/net/ipv4/netfilter/ip_tables.ko': No such file or directory
iptables v1.3.6: can't initialize iptables table `filter': iptables who? (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.

anyway its very easy to fix and i just decided to share the info, just type a simple command:

depmod

extra = 'console=hvc0 xencons=tty'

$ ssh root@xxx.xxx.xxx.xxx
The authenticity of host ‘xx.xx.xxx.xxx (xx.xx.xxx.xxx)’ can’t be established.
RSA key fingerprint is replaced for security.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added ‘xx.xx.xxx.xxx’ (RSA) to the list of known hosts.
Password:
PTY allocation request failed on channel 0

In the above scenario, you can see that I logged in but I’m not able to get into the console.

Once you’re in debug more, you will see lots of messages elaborating the SSH access steps in detail. These messages might point you to the root cause or the stage at which you’re being locked.

In my case, I got freezed after authenticating myself.

Resolution is just to make pts and restart sshd

mkdir /dev/pts
mount /dev/pts
/etc/init.d/ssh restart

and permanent solution is just instaling udev via:

apt-get install udev

Linux run levels are numbered 0 through 6. Run levels stop at six for practical and historical reasons, but it is entirely possible to have more if desired.

The following table summarises the UserLinux run levels:

 * 0		System Halt
 * 1		Single user
 * 2		Full multi-user mode (Default)
 * 3-5		Same as 2
 * 6		System Reboot

When run levels are discussed they are referred to as ‘moving into’, or ‘going into’ a certain run level. The inference is that you came from somewhere. With the exception of booting up, a system always transitions from one runlevel to another in response to certain conditions.

Special Run Levels

Run level 0 is the system halt condition. Nearly all modern X86 computers will power off automatically when run level 0 is reached. Older X86 computers, and various different architectures will remain powered on and display a message referring to the halt condition.

Run Level 1 is known as ‘single user’ mode. A more apt description would be ‘rescue’, or ‘trouble-shooting’ mode. In run level 1, no daemons (services) are started. Hopefully single user mode will allow you to fix whatever made the transition to rescue mode necessary.

(You can boot into single user mode typically by using your boot loader, lilo or grub, to add the word ‘single’ to the end of the kernel command line).

Run levels 2 through 5 are full multi-user mode and are the same in a default UserLinux (Debian) system. It is a common practise in other Linux distributions to use run level 3 for a text console login and run level 5 for a graphical login.

Run level 6 is used to signal system reboot. This is just like run level 0 except a reboot is issued at the end of the sequence instead of a power off.

In the interests of completeness, there is also a runlevel ‘S’ that the system uses on it’s way to another runlevel. Read the man page for the init command (“man init“) for more information, but you can safely skip this for all practical purposes.

Where Does a Run Level Live?

Like everything else in a Linux system, run levels are defined by files in the filesystem. All the run level files are found in the /etc directory according to the following table:

/etc/rc0.d		Run level 0
/etc/rc1.d		Run level 1
/etc/rc2.d		Run level 2
/etc/rc3.d		Run level 3
/etc/rc4.d		Run level 4
/etc/rc5.d		Run level 5
/etc/rc6.d		Run level 6

Notice a pattern? Each defined runlevel should have an rcX.d directory where X is the run level number. The contents of the rcX.d directory determines what happens at that run level.

(S)tart files, (K)ill files

Let’s look at run level 2 since this is where we’ll spend most of our time.

Here are the contents of a generic rc2.d directory:

S10sysklogd  S20cupsys   S20mailman  S20usermin  S91apache         S99xdm
S11klogd     S20exim4    S20makedev  S20xfs      S91apache2
S14ppp       S20fam      S20pcmcia   S20xprint   S99gdm
S18portmap   S20hylafax  S20samba    S89atd      S99rmnologin
S20acpid     S20inetd    S20ssh      S89cron     S99stop-bootlogd

At first glance the files in this directory look kind of intimidating. They should be. The files in the rcX.d directories are formatted for the computer to read, not the user.

Each file is a symbolic link to a script residing in the /etc/init.d directory and controls the starting, or stopping of a program, or daemon (service).

This is important enough to say again, each file is a symbolic link to a script and controls the starting, or stopping of a program, or daemon.

In slightly modified man page format, here is how the files are named:

[K | S] + nn + [string]

Working backwards, here is how the name parses out. The [string] is a human readable mnemonic for the executable file that is actually symbolically linked to. The ‘nn’ is a two digit number from 01-99; lower number programs are executed first. By this method, services that have a dependancy can be certain their precursor has ran. The K and S signify simply Kill, or Start.

When a system moves into a new runlevel, all the files that begin with S will be executed. When a system moves into a new runlevel all the files that begin with K will be executed. Yes, all the files will execute, but with one distinct difference: ‘S’ files invoke their program with the ‘start’ parameter, the ‘K’ files invoke their program with the ‘stop’ parameter. The UserLinux (Debian) system optimizes the runlevel change by not starting a daemon that is already running.

The simple elegance of this system is made possible by the alphabet. All the scripts will execute in alphabetical order. ‘K’ comes before ‘S’, so programs are stopped before they are started. Forgetting this fact can lead to a lot of chin scratching while manipulating your rcX.d files.

After the first letter comes the integer, again determining execution order. Finally, the mnemonic portion is followed alphabetically to determine execution order.

Let’s look at some of the programs that are actually executed during a run level change:

S20exim4 -> ../init.d/exim4
S20fam -> ../init.d/fam
S20hylafax -> ../init.d/hylafax
S20inetd -> ../init.d/inetd
S20mailman -> ../init.d/mailman
S20makedev -> ../init.d/makedev
S20pcmcia -> ../init.d/pcmcia
S20samba -> ../init.d/samba
S20ssh -> ../init.d/ssh

All of these files have the same precedence as far as the system is concerned. They will be executed in the order listed, i.e. alphabetically.

All of the scripts that run during system start-up actually reside in the /etc/init.d/ directory, as suggested by the listing. The reasons for this are many, but basically boil down to common sense issues like: saving space, single point for editing, and everyone knowing where to find things.

Transitioning Between Run levels

When you leave a runlevel, nothing happens. All the action takes place when you enter the new run level.

Look at the following two rcX.d listings:

rc2.d:

K01xdm      S18portmap S20fam     S20makedev S20usermin S89cron    S99rmnologin
S10sysklogd S20acpid   S20hylafax S20pcmcia  S20xfs     S91apache  S99stop-bootlogd
S11klogd    S20cupsys  S20inetd   S20samba   S20xprint  S91apache2 S99xdm
S14ppp      S20exim4   S20mailman S20ssh     S89atd     S99gdm

rc3.d:

K01gdm       S20acpid    S20inetd    S20ssh      S89cron           S99xdm
S10sysklogd  S20cupsys   S20mailman  S20usermin  S91apache
S11klogd     S20exim4    S20makedev  S20xfs      S91apache2
S14ppp       S20fam      S20pcmcia   S20xprint   S99rmnologin
S18portmap   S20hylafax  S20samba    S89atd      S99stop-bootlogd

Look intensely at the two listings while allowing your eyes to unfocus. An image of a gnu will eventually appear. Ok, no it won’t, but you believed for just a second, didn’t you?

Look at the first listing, rc2.d. Notice the contradiction between the first program and the last program. K01xdm instructs the system to Kill xdm upon entering run level 2; S99xdm tells the system to start xdm. Who wins? Both programs are executed, but the last program to run will prevail. S99xdm, as it appears last in the alphabetical sequence, will leave xdm in a running state. The change to runlevel 2 was wasted typing.

Now, let’s look closely at the rc3.d listing. The first thing that will be executed is the stopping of gdm, which is the default graphical display manager for UserLinux (Debian). Note the S99gdm file (symlink) has been removed. The purpose of the change is to move to a runlevel where everything else is still running, except the pretty window manager. This situation is called ‘console mode’. As mentioned previously, many Linux distributions use run level 3 for console mode.

That’s great, but how do I change run levels?

Before we change run levels it might help to find out which run level is current. Use the ‘runlevel‘ command to tell you two things: The last run level, and the current run level. Here is the command and the output shown together due to the sparsity of the output:

ulsoho:/home/user1# runlevel
N 2

The ‘N’ stands for none, meaning there has been no run level change since powering up.

The init system controls run levels, but then again, the init system pretty much controls everything. The init system will be looked at in detail in a future article.

The primary command used to change run levels is ‘telinit‘. Get it? “Tell Init” to do something; like this:

telinit 3

telinit takes one argument on the command line. As always, see the man page for full details. Normally the argument will be one of: 0,1,2,3,4,5,6, or the letter ‘S’. As you may have guessed, the numbers correspond to the run level you wish to move to. Using the ‘S’, for single-user, is the same as the number 1, but don’t do it; the ‘S’ runlevel is intended for use by the UserLinux (Debian)system.

A note of caution is warranted here. You can easily use the telinit command to reboot (run level 6), or shutdown (run level 0) the system, but it is not recommended. Certain programs need special processing for an orderly shutdown. Bypassing the expected shutdown sequence can have dire effects on your data. Older _Unix_ systems are especially sensitive to shutdown/bootup operations

The preferred method for a serious runlevel change is ‘shutdown‘. There are easier mnemonics, but in a running system they all point to the ‘shutdown‘ command. You can use the ‘halt‘, or ‘poweroff‘ command to stop a system and the ‘reboot‘ command to restart your system. In each case they call the ‘shutdown‘ command with different parameters.

In a single system (non-networked, or no locally shared resources) environment, the shutdown choice is pretty much yours. However, in a multi-user production system the rule of thumb is learn the shutdown command. The two most basic uses of the ‘shutdown’ command are for halting, or rebooting. The important parameter to know for shutdown is WHEN is the action going to occur. Here is the command synopsis from the shutdown man page:

/sbin/shutdown [-t sec] [-arkhncfFHP] time [warning-message]

The vast majority of your shutdowns will follow one of these two forms:

shutdown -h now

or to reboot instead of halt:

shutdown -r now

Intuitively, the arguments mean ‘halt‘ and ‘reboot‘, respectively.

In a multi-user system like a file server, the most important parameter is ‘time’. The time can be an actual clock time in the form of HH:MM, or a Julian style shutdown X minutes from now, denoted by the +X syntax. Note that the ‘+’ is needed. The keyword ‘now‘ is synonymous with ‘+0′. Here are two examples using the time parameter:

shutdown -h 16:30
shutdown -r +10

Another important point to remember: once the shutdown command is issued, a notice is sent to all the users of the system and no further logins are allowed. For example, if you need to bring the system down at midnight, don’t issue the shutdown command at noon and leave to take a nap. No new users will be able to login for the next 12 hours.

A good admin never takes a system down without warning the user community, but the shutdown notice is only sent after the command is executed! Fortunately, there are two ways around the downtime notification dilemma. The first is the ‘motd’, Message Of The Day. The motd is a useful feature that is often overlooked. Using the motd is easy and you are urged to read the simple man page for details. The second method of notification is the -k option. Using -k will send the downtime notice to all the users, but will not actually start the shutdown sequence. There is an important limitation to the shutdown notification: the downtime message is only sent 15 minutes (or less) prior to the actual shutdown.

The warning-message parameter may be useful for…high maintenance users. I find that the default message is authoritative and simple enough to accomplish the task.

Troubleshooting in Run Levels

Here is a tip contributed by Nicholas Petreley. Sometimes you may not want all the programs in a run level to execute. In this situation an easy way to disable a program is to rename it with the initial S, or K in lowercase. The system will ignore all programs that do not begin with a capital S, or K.

(UserLinux is a subset of Debian. Everywhere ‘UserLinux’ appears, you can substitute ‘Debian’ with equal facility.)

You want to use Linux and OpenSSH to automize your tasks. Therefore you need an automatic login from host A / user a to Host B / user b. You don’t want to enter any passwords, because you want to call ssh from a within a shell script.

How to do it

First log in on A as user a and generate a pair of authentication keys. Do not enter a passphrase:

a@A:~> ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/a/.ssh/id_rsa):
Created directory '/home/a/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/a/.ssh/id_rsa.
Your public key has been saved in /home/a/.ssh/id_rsa.pub.
The key fingerprint is:
3e:4f:05:79:3a:9f:96:7c:3b:ad:e9:58:37:bc:37:e4 a@A

Now use ssh to create a directory ~/.ssh as user b on B. (The directory may already exist, which is fine):

a@A:~> ssh b@B mkdir -p .ssh
b@B's password:

Finally append a’s new public key to b@B:.ssh/authorized_keys and enter b’s password one last time:

a@A:~> cat .ssh/id_rsa.pub | ssh b@B 'cat >> .ssh/authorized_keys'
b@B's password:

From now on you can log into B as b from A as a without password:

a@A:~> ssh b@B hostname
B

A note from one of our readers: Depending on your version of SSH you might also have to do the following changes:

• Put the public key in .ssh/authorized_keys2
• Change the permissions of .ssh to 700
• Change the permissions of .ssh/authorized_keys2 to 640

We are pleased to announce the immediate availability of CentOS-5.3 for the i386 and x86_64 Architectures.

CentOS-5.3 is based on the upstream release EL 5.3.0, and includes packages from all variants including Server and Client. All upstream repositories have been combined into one, to make it easier for end users to work with. And the option to further enable external repositories at install time is now available in the installer.

This is just an announcement email, not the release notes. The Release Notes for CentOS-5.3 can be found on-line at : http://wiki.centos.org/Manuals/ReleaseNotes/CentOS5.3 and everyone is encouraged to look through them once. Also worth browsing through at the CentOS FAQ’s at http://wiki.centos.org/FAQ

+++++++++++++++++++++++
ArtWork update:

CentOS-5.3 brings in a completely new artwork stack. A big thanks to Alain Reguera Delgado, Ralph Angenendt, Marcus Moeller and everyone on the Artwork SIG for bringing us the best, most comprehensive artwork set yet. Also a big thanks to all the translation teams for their contributions to the installer artwork.

+++++++++++++++++++++++
Contrib repos are back:

Given the widespread requests for user contributed packages directly being hosted within the centos repositories, the contribs repository is now back with CentOS-5.3. There are no packages yet, but over the next few weeks we hope to have a policy and process in place that allows users to submit and manage packages in the contrib repo.

+++++++++++++++++++++++
Upgrading from CentOS-5.2 ( or CentOS-5.0 / 5.1 ):

If you are already running CentOS-5.2 or an older CentOS-5 distro, all you need to do is update your machine via yum by running :

‘yum update’

Running ‘yum list updates’ before doing the update is recommended, so you can get a list of packages that are going to be updated. To check you are indeed on CentOS-5.3, run : ‘rpm -q centos-release’ and that should return: ‘centos-release-5-3.el5.centos.1′

+++++++++++++++++++++++
Upgrading from CentOS-2.1 or CentOS-3.x or CentOS-4.x:

The only recommended way to update from an earlier version of CentOS is to download and run a fresh install. In some cases, running the installer with the ‘upgradeany’ option might also achieve the desired results, however you are strongly recommended to look at the CentOS Wiki where hints and notes about potential upgrade paths from CentOS-4/3/2.1 to CentOS-5 are provided.

+++++++++++++++++++++++
Downloading CentOS-5.3 for new installs:

When possible, consider using torrents to run the downloads. Not only does it help the community and keeps mirrors from running up high bandwidth bills, in most case you will find its also the fastest means to download the distro. There are present over a thousand people already seeding CentOS-5.3 and its possible to get upto 100mbps downloads via
these torrents.

– Via BitTorrent :
CD:
http://mirror.centos.org/centos/5.3/isos/i386/CentOS-5.3-i386-bin-1to6.torrent
http://mirror.centos.org/centos/5.3/isos/x86_64/CentOS-5.3-x86_64-bin-1to7.torrent

DVD:
http://mirror.centos.org/centos/5.3/isos/i386/CentOS-5.3-i386-bin-DVD.torrent
http://mirror.centos.org/centos/5.3/isos/x86_64/CentOS-5.3-x86_64-bin-DVD.torrent

– Via direct download:
Due to bandwidth considerations the CentOS Project does not publish ISOS directly from our network machines. However direct downloads are available from external mirrors over http, ftp and rsync, and a geoip based list is available at http://isoredirect.centos.org/centos/5/isos/ to give you the best predictable match ( and only lists mirrors that are
updated already, so you dont need to waste time looking for a sync’d mirror )

Some mirrors also publish DVD images that can be downloaded directly. Refer to the mirrors list page at http://www.centos.org/mirrors for more details Mirrors that offer DVD’s are clearly marked on the page.

sha1sum for these ISOS:

i386:
4b454d76d06daa0b1772115e9b95c9465a4cecb0 CentOS-5.3-i386-bin-1of6.iso
0da3292ea1d90639714a5e7d77812568bc01ec05 CentOS-5.3-i386-bin-2of6.iso
77e867eb736b58f31cdd25c4835643ab795979e2 CentOS-5.3-i386-bin-3of6.iso
949ee93440e736c8414fb8b571178970a31e6675 CentOS-5.3-i386-bin-4of6.iso
5eafdea33c18f623bb9299ae624b8c8a12132bfa CentOS-5.3-i386-bin-5of6.iso
90ae5387a38f8ec805d877cc5525ae8dedc7f810 CentOS-5.3-i386-bin-6of6.iso
b7f85a3a493e3051e50515ef881214929c88a5f3 CentOS-5.3-i386-bin-DVD.iso
a0c640ae0c68cc0d9558cf4f8855f24671b3dadb CentOS-5.3-i386-netinstall.iso

x86_64:
7327174dc0cbb6531bc0e2f26e24788251717e91 CentOS-5.3-x86_64-bin-1of7.iso
d060ed2826a4c212eebf5e3a825ce75e77cb44e0 CentOS-5.3-x86_64-bin-2of7.iso
a0b7471ec6b742c962cc06b69624b0746025005f CentOS-5.3-x86_64-bin-3of7.iso
fe4106322d6b08344e82df8904142664a8a82522 CentOS-5.3-x86_64-bin-4of7.iso
8cb5539fa4241bc5d23798a3e2721b2ebd3b18fe CentOS-5.3-x86_64-bin-5of7.iso
8a8f32888279f701e15162dec6f52b5f5fb5effc CentOS-5.3-x86_64-bin-6of7.iso
f053b05ea8576ea7d72116fa246f914086238ca9 CentOS-5.3-x86_64-bin-7of7.iso
f8ca12b4acc714f4e4a21f3f35af083952ab46e0 CentOS-5.3-x86_64-bin-DVD.iso
e971bd1677622708348b8a65264ec360a1cc0196 CentOS-5.3-x86_64-netinstall.iso

+++++++++++++++++++++++
Pending CentOS-5.3 Updates and src.rpm’s

Updates have been issued from upstream since they released 5.3, a bulk of these updates are already released into CentOS-5.3 and are available immediately. All pending updates will be released within the next 48 hrs. To keep the initial release size smaller, the src.rpm’s are also going to be slowly released into the mirrors over the next 48 hrs along with debuginfo packages.

+++++++++++++++++++++++
Release Notes:

The distro release notes are only available online at http://wiki.centos.org/Manuals/ReleaseNotes/CentOS5.3 The release notes include important changelog info as well as notes about the installer and outcomes from test situations which the centos-qa team worked through. Its considered essential reading.

Upstream release notes are available in the NOTES/ directory of the install media. These include release specific technologies, new features in the distro and other misc infomation that can help you better utilise the distro.

+++++++++++++++++++++++
Getting Help:

The best place to start when looking for help with CentOS is at the wiki ( http://wiki.centos.org/GettingHelp ) which lists various options and communities who might be able to help. If you think there is a bug in the system, do report it at http://bugs.centos.org/ – but keep in mind that the bugs system is *not* a support mechanism.

Some Friendly URL’s :
http://www.centos.org/
http://wiki.centos.org/
http://lists.centos.org/
http://bugs.centos.org/
irc://#centos@irc.freenode.net

+++++++++++++++++++++++
A big thanks to everyone who contributed, including the translation teams, the qa team, the CentOS Developers and all the users out there. I would also like to thank all the users for their patience and help!

Enjoy this release, tell all your friends about it too.

–
Karanbir Singh
CentOS Project { http://www.centos.org/ }
irc: z00dax, #centos@irc.freenode.net

Sadly that is not the case with Citrix’s new Xen 5.0 Virtual server software. There are issues with XenDesktop’s ability to deliver Virtulaized Windows 2008 Server desktops and XenServer will not run the OS Natively. This flaw takes away from the opening up of the RAM support in Xen Express which was limited to 4GB but now supports up to 128GB

This short coming will hurt the VM hopeful as many people currently using VMware and Sun’s Virtual Box have no problems with Microsoft’s latest server OS.

XEN 5.0 compatible operating systems listed here.

There is a work around to this for Citrix’s XenServer if you want to spend the time here.

Game Changing Move Goes Well Beyond Free Hypervisors to Accelerate the Adoption of World-Class Virtual Infrastructure for Both Enterprises and Cloud Providers

BOSTON » 2/23/2009 » Citrix Systems, Inc. (Nasdaq: CTXS), the global leader in application delivery infrastructure, today unveiled a groundbreaking new version of Citrix® XenServer™ – the company’s enterprise-class, cloud-proven virtualization platform – that will be offered free of charge to any user for unlimited production deployment.  While basic hypervisors have been free for years, most have had limited practical use in real world environments.  With this new release, XenServer sets an entirely new standard for free virtualization with the addition of powerful new features like centralized multi-node management, multi-server resource sharing and full live motion.  Dramatically lowering the entry price of virtualization also helps address today’s challenging economic climate by making enterprise-class virtualization far more accessible to businesses of all sizes, regardless of budget.

Now in production in more than 5,000 enterprise datacenters worldwide, XenServer is a key component of the Citrix Delivery Center™ product family, a comprehensive datacenter-to-desktop system that helps customers transform static datacenters into dynamic “delivery centers.”  XenServer is powered by the same Xen® virtualization engine that runs most every independent cloud today, including the largest single virtualization deployment in the world.  With more than 75 percent of corporate servers worldwide still not virtualized**, today’s announcement helps accelerate the adoption of virtualization by bringing the simplicity, scale and economics of the cloud to enterprise datacenter for the first time ever.

“Free hypervisors with limited functionality have been around for a long time. We see this move as substantially different because it offers a competitive, enterprise-ready virtual infrastructure platform with full centralized management, live motion and support for unlimited virtual machines and servers – with no strings attached,” said Mark Bowker, analyst, Enterprise Strategy Group.  “This is a very positive move that has the potential to accelerate the adoption of virtualization for enterprise customers of all sizes and make it easier for external cloud providers to add full Windows support to their existing Linux offerings.  Anyone who dismissed XenServer in the past as a legitimate player in enterprise virtualization clearly owes it to themselves to take a look at this offering.”

Enterprise-Class, Cloud-Proven Virtualization
The new Citrix XenServer release provides customers with a robust, scalable, feature-rich virtualization platform that is exceptionally powerful, yet incredibly easy to learn and use. Core features of XenServer include the following:

• Powerful Centralized Management enables full multi-node management for an unlimited number of servers and virtual machines; includes easy physical-to-virtual and virtual-to-virtual conversion tools, centralized configuration management and a resilient distributed management architecture
• Live Motion and Multi-Server Resource Sharing incorporates powerful XenMotion™ technology that allows virtual machines to be moved from server to server without service interruption for zero downtime; also includes optimal initial virtual machine placement and intelligent maintenance mode
• Proven Hypervisor Engine powered by the 64-bit industry standard Xen open source hypervisor developed jointly by more than 50 leading technology vendors, enabling users take full advantage of the latest performance, security and scalability enhancements in next-generation servers, operating systems and microprocessors
• Fast Bare Metal Performance supports an unlimited number of servers and virtual machines with industry-leading consolidation ratios, near native performance on the most challenging application workloads, and virtually zero overhead in both Microsoft Windows® and Linux environments
• Easy Setup and Administration features familiar interface with easy wizard-driven configuration, intuitive Web 2.0 style search, and built-in auto-help that makes the learning curve for new administrators a snap
• Integrated Storage Management that supports any existing storage system; includes built-in storage management features such as host-based logical volume management, and dynamic multi-pathing capabilities

“This move is all about accelerating the adoption of virtualization by tearing down the barriers of cost and complexity that have been in place for far too long,” said Simon Crosby, CTO, Virtualization Management Division, Citrix.  “The faster we can help customers virtualize the millions of servers that remain unvirtualized today, the sooner they can start adding significant value on top, transforming static datacenters into dynamic delivery centers where every application, desktop and server workload is delivered as an on-demand service.”

Good for All Types of Customers
With the new free XenServer release, corporate customers now have everything they need to deploy and centrally manage full enterprise-class virtualization on any number of servers with no upfront costs – especially significant during difficult economic times.  As a result, customers who are new to virtualization can now begin realizing all of its efficiencies and cost savings sooner, upgrading to more advanced virtualization management features when and if they need them down the road.  Customers who have already made an investment in more expensive virtualization platforms in the past, now have a proven enterprise-class alternative to consider when it comes time to upgrade or expand their existing deployments.

The new free XenServer release is also great news for cloud providers, the vast majority of whom use the open source Xen hypervisor today as a core component of their platforms.  By upgrading to the full XenServer product, these cloud vendors not only gain a far richer virtual infrastructure platform at no cost, they also get instant native support for Windows guests in addition to the Linux guests they offer today.  This will also make it easier for Linux OS vendors who currently include Xen in their products to move to the full XenServer, giving their customers far more value and focusing their development efforts on adding differentiated services on top of the virtualization platform.

“The Xen virtualization engine has been a key component of SoftLayer’s cloud computing strategy, providing the performance scalability and track record we have needed to achieve our vision of using virtualization to transform the datacenter,” said Nathan Day, CTO, SoftLayer.  “With this move today by Citrix, we can gain even further leverage using the full power of XenServer in our next-generation cloud computing platform with more efficiency and richer functionality than ever before.  XenServer, as part of the Citrix Cloud Center (C3) platform, is really leading the way in the emerging cloud segment by helping its customers and partners navigate the rapidly-evolving technology.”

As a result of this move, XenServer will also now be included as a core feature of Citrix® XenApp™, the company’s flagship application virtualization product line.  Adding XenServer as the base platform under XenApp increases flexibility and helps customers consolidate the number of physical servers in production with virtually no overhead.  More than one million servers in enterprise datacenters today are running XenApp.

Step up to Advanced Virtualization Management When Ready
Customers who wish to add more advanced virtualization management capabilities in the future will also be able to purchase  Citrix Essentials™ for XenServer, a new product line that includes a rich set of capabilities specifically optimized for the XenServer environment (please see today’s separate announcement).  These optional features – including lab automation, dynamic provisioning, workflow orchestration, high availability and seamless integration with leading storage systems – will be directly visible from the XenCenter™ console in grayed-out mode, making it easy for XenServer administrators to understand the additional capabilities available to them for additional purchase should their needs change over time.  As Citrix adds new enhancements to the Citrix Essentials product line, all active XenServer users will be notified of these new capabilities automatically through their XenCenter management console.

Availability
The new free Citrix XenServer release will be available for download from the Citrix website and other download portals by the end of March 2009.  Citrix Essentials for XenServer will be available from Citrix resellers on April 7, 2009.  Customers who would like to experience a preview of the new XenServer release, as well as get a sneak peek into some of the new features in Citrix Essentials, can download a free trial version today at http://www.citrix.com/freexenserver

About Citrix Systems, Inc.
Citrix Systems, Inc. is the global leader and the most trusted name in Application Delivery Infrastructure. More than 215,000 organizations worldwide rely on Citrix to deliver any application to users anywhere with the best performance, highest security and lowest cost. Citrix customers include 100 percent of the Fortune 100 companies and 99 percent of the Fortune Global 500, as well as hundreds of thousands of small businesses and prosumers. Citrix has approximately 8,000 partners in more than 100 countries. Annual revenue in 2008 was $1.6 billion.

For Citrix Investors
This release contains forward-looking statements which are made pursuant to the safe harbor provisions of Section 27A of the Securities Act of 1933 and of Section 21E of the Securities Exchange Act of 1934.  The forward-looking statements in this release do not constitute guarantees of future performance.  Investors are cautioned that statements in this press release, which are not strictly historical statements, involve a number of factors that could cause actual results to differ materially, including risks associated with the uncertainty in the IT spending environment and a downturn in economic conditions generally, revenue growth and recognition of revenue, products, their development and distribution, product demand and pipeline, competitive factors, the Company’s key strategic relationships, acquisitions and related integration risks as well as other risks detailed in the Company’s filings with the Securities and Exchange Commission. Citrix assumes no obligation to update any forward-looking information contained in this press release or with respect to the announcements described herein.

One of the thing that astonished me is the fact that (even if not written in Upstream RN) some drivers seem to have been updated. For example the sky2 module didn’t support the Marvel gigabit 88E8056 nic since 5.1 .. but .. :

[arrfab@waldorf ~]$ modinfo /lib/modules/2.6.18-92.1.22.el5/kernel/drivers/net/sky2.ko |grep alias|wc -l
29
[arrfab@waldorf ~]$ modinfo /lib/modules/2.6.18-128.el5/kernel/drivers/net/sky2.ko |grep alias|wc -l
30
Interesting , isn’t it ? (especially for people having that kind of low-level entry nic in their workstation ..)

Other interesting stuff is the newer scsi-target-utils (aka tgtadm/iScsi target) that now includes a config file and two helpers to setup a new iscsi lun easily (tgt-setup-lun and tgt-admin) .. of course there are other new good things so stay tuned for more informations and of course, don’t forget to read the Release Notes when they’ll be published !