Deep dive into VMware's virtual infrastructure
VI 3 swims through our server consolidation test, demonstrating some amazing capabilities and a few quirksFollow @infoworld
P2V Assistant is based on an old Knoppix Live CD, which is booted on the source server. When (and if) all storage and network devices are discovered and configured, you can use a text-based menuing system from the source server console to migrate the server to a VM on a specific destination server. Interestingly, given its Linux roots, P2V Assistant has an easier time with Windows servers than Linux servers, and with newer server hardware than older gear. P2V Assistant had trouble detecting the RAID and NIC hardware in our Dell PowerEdge 2950 and 850 servers, but flawlessly inventoried an HP ProLiant DL360 G3. The migration from physical to virtual took only about 10 minutes, and correctly resized the destination disk, necessary because the source server had more than 60GB of unused space in the primary partition. As soon as the migration was finished, we booted the new VM and powered off the old server. Other than the downtime caused by booting the domain controller from the CD, we encountered no other problems
For the next migration, we put the new VMware Converter tool to the test. This tool offers both live and offline migration options. The live version runs as a stand-alone application on a Windows server. For this test, the Microsoft Exchange Server 2003 system was selected for migration. Converter has a simple interface that allows admins to supply a Windows server name or IP address and log-in credentials, modify settings for the destination VM, and optionally resize partitions. After that, it’s simply a matter of clicking a button to convert the server. During the course of the conversion, we added several users and Exchange mailboxes to the domain to see how complete a live conversion could be under normal operations. In production, you wouldn’t want to migrate any servers running databases, e-mail, or other datacentric tasks in this way, but it was a good opportunity to test the thoroughness of the tool. Of the three users added to the Exchange server, the first two, which were added during the first half of the migration, were present in the resulting VM. The last user, added when the migration was 85 percent complete, was present in Active Directory but missing a mailbox. In addition, the Exchange services failed to start when the Exchange Server VM was initially booted, but they did start manually, and the server appeared to suffer no ill effects from the migration. This form of P2V is certainly attractive, because it requires no real downtime, but should be used only in cases of largely quiescent servers, or for servers with static tasks, such as Web servers and file servers with external storage.
We also tried Converter’s offline mode. As with P2V Assistant, this requires booting the server from a CD into a limited OS. Unlike P2V Assistant, however, Converter’s CD is built on Windows PE, a curious decision. Converter required far more time to boot than the Linux-based P2V Assistant, and it didn’t offer any better hardware detection.
The next migration was the Fergenschmeir file server, a white-box server built from spare parts. Because the CD-based methods weren’t likely to recognize the mishmash of hardware, this server was migrated live with VMware Converter. On top of the live migration, we put the server under heavy load at the time, pushing nearly 100MB per second to simulated users. There was even a third wrinkle to this plan: the bulk of the files being served were residing on an iSCSI LUN.