Doing a physical-to-virtual (P2V) server migration is a new experience for many systems administrators, and the...
process is often one of trial and error.
Certainly, there are tools to automate the P2V process, but some IT managers prefer to do a fresh install and to go it alone.
Kevin Hsieh of the Bay Alarm Co. in California has migrated several applications, including Internet Information Services (IIS), print, file, Exchange, and domain controllers over to virtual machines (VMs) on Microsoft Virtual Server 2005.
Lower licensing costs for the OS (operating system) on virtual versus physical systems, Double-Take software (used for data protection), easier provisioning of systems, better hardware utilization, and lower power, cooling and management costs were all key factors in the decision to go virtual, Hsieh said.
"We were able to consolidate several boxes that were under people's desks into the datacenter so that we can better manage and keep track of the systems. This also greatly enhances our [disaster recovery] capability," Hsieh said.
To make the move, Hsieh used native migration re-installation methods. "I didn't do any straight P2V migrations because I wanted the new system to be clean. The old systems were running Windows 2000, and I didn't want any garbage from the old system being migrated to the new system," Hsieh said. "The P2V part went just as well as any other normal migration to new hardware and OS would."
Hsieh learned a lot doing the P2V migrations manually. "I've seen an issue where I think that I allocated too much RAM to the guests and not enough to the host OS [running Virtual Server 2005 R2 on Windows 2003 R2 x64]. I've also had to be sure that I didn't do anything that would put a lock on the disk images for too long while the VMs were active, or else they blue screen because they can't write to disk," he said.
The end result is that the data center now has more OSes running in virtual environments than physical ones. They consolidated further by powering down, removing several old servers and putting old systems onto newer existing hardware, he said.
"Service levels are just as good as they were before, and now we have less worries about the underlying hardware and drivers," Hsieh said.
Hsieh still has more applications and database servers to virtualize. "I want to migrate them to a new OS instance so I understand the configuration and I know that the new installation is clean. Otherwise, I can just do a P2V migration, but I won't have an understanding of how the system is set up, and it will still have legacy garbage hanging around from old apps, drivers and operating systems," Hsieh said.
Paul Keen, systems administrator for the Florida Christian Schools system performed a P2V to separate two services running on a single physical machine. The machine originally ran sendmail for email and Apache 1.2 for its Web site.
"When we decided to switch to Microsoft Server Exchange, we needed the physical server that sendmail already was running to run Exchange. This left a problem for our Web site, since we could not run it in IIS/Windows due to a Linux-based application we were running. The only solution I could come up with was to do a P2V," Keen said.
Using VMware Server, Keen set up a VM running FreeBSD and installed the latest version of Apache and any other necessary software.
Keen then used rsync -- a program that synchronizes files and directories between Unix and Linux systems -- to transfer all Web site-related files to the virtual machine while the original server was still running. The original server was taken offline to rsync the files again, he said.
Using rsync once while the site was online and once again while it was offline allowed the site downtime to be minimal. If Keen had transferred all the files while the server was offline, downtime could have been hours, he said.
The original server was then removed from the network and its IP address was assigned to the new VM. At this point, Keen brought the Web site back online on the new virtual machine.
Total downtime was only a couple of minutes, he said.
"The only thing that went wrong was I did not transfer/back up the email contacts that some of our users had saved to a different location. This was caused by poor planning on both my part and the consultant we hired to handle the mail transfer," Keen said. "The actual P2V had no problems. I think that setting up a second identical server and transferring only the data is the best way to handle a P2V ... less potential for problems."
Keen is, well, keen to virtualize more systems. "We may do more P2Vs over the next six months in an effort to reduce power consumption and, more importantly, move older servers from aging hardware onto more current hardware. Since our school does not have much of a budget, we are running a few servers on workstation hardware," Keen said. "With P2V migrations, we should be able to virtualize these machines and move them to our existing server class machines."
Let us know what you think about the story; email: Bridget Botelho, News WriterYou can also comment on and read more about IT pros' P2V experiences on our blog.