In the days before virtualization, migrating physical systems from one SAN to another was a time consuming and cumbersome process. First you had to connect the computer system in question to both SAN’s and then perform some form of data copy from one disk to the other, taking care to preserve permissions, modification dates, and other file meta data. One mangled permission or mod date could wreck havoc with business applications. Virtualization has certainly changed all of that. Now, entire computer systems are contained within a one or more virtual disks that can be easily moved from one SAN volume to another. Unfortunately, this still requires a downtime for that particular VM; or at least it did.

Through the use of Storage VMotion, included in Virtual Infrastructure 3, administrators now have the ability to move a running virtual machine from one volume to another without even the slightest disruption of service. Only there is yet another catch, the stock tools provided by VMware can only be used at the command-line and requires a whole lot of options. The end result is a process that is complicated and generally requires a good amount of trial and error. Fortunately, someone has created a nifty Virtual Infrastructure Client plugin that does a marvelous job of simplifying the task. The plugin is called “vip-svmotion” and you can find more information, as well as download links for it here.

I just installed the plugin, enabled it under the plugins menu and kicked off a test migration. Not only did the migration go exactly as advertised, I saw no external indicators that the system was being moved from one SAN to the other. The only hiccup I encountered was that the tool would not move a VM with snapshots. In most cases, I had no problem dropping the snapshots.

The plugin adds a context menu option for any given VM called “Migrate Storage…”. Once you right click on a VM and select this option, you’ll be created to a dialog that lists all of the data stores and the VM you wish to move. Simply drag the VM to the new data store and click apply. I’m serious, it really is that simple.

Now, the only thing that irks me about this plugin is that VMware didn’t build the functionality into the VI client themselves.

Until recently, the only downside I ever encountered was the occasional inconvenience caused during a VI3 wide outage. In those cases were a problem is currently impacting the entire VI3 environment, you are forced to perform your management by connecting directly to each ESX host in the cluster. Typically, I’ll zero in on the ESX node hosting the VC server and get that working first. Last night, I encountered my first problem with a virtual VirtualCenter server hosted on the cluster it manages.

Despite all their redundancy and fault-tolerance, storage area networks will occasionally go down; and for me that was last night. I was able to quickly identify the problem and get the SAN back online, but nearly all of the virtual machines crashed hard. Among the dead was the virtual VirtualCenter server. As usual, I zeroed in on the node with the VC server and tried to reset the VM. It was at this point that ESX informed me that it couldn’t do that for me because it couldn’t contact the license manager. This was puzzling because the individual ESX nodes are supposed to cache the licensing data for fourteen (14) days. Apparently, this wasn’t working for some reason. Until the nodes could see a valid license server, nothing was coming back online.

Ultimately my colleague downloaded the software and license from the VMware support pages and deployed a new license server on one of our physical systems on the network. Once complete, I pointed the ESX nodes to the new license server and we were golden. I think I’ll be building a new dedicated VC server on a DL380 and take the “virtual” out of the “virtual VirtualCenter server”.

Dandyman.us is my personal weblog for a number of personal hobbies including web design, guitar, and gaming. I use the site to post tutorials, information, and commentary on a variety of topics.

The site is powered by WordPress, as most of my sites are, and features a highly customized version of Evan Eckard’s Notepad Chaos theme. The theme was released by Smashing Magazine for the WordPress community and it has been my most ambitious design customization to date. Extensive XHTML code changes and some significant changes to the original Photoshop design have taken a Evan’s theme in a completely different direction.