Storage Technology News:
VMware users long for live data migration
17 May 2006 | SearchStorage.com
James Jancewicz, a storage specialist for a large health insurance provider based in New England, leases storage arrays from IBM that expire every three years and a new array is put in place.
"When I'm upgrading those arrays, there's no way for me to use VMotion to point VMware guests at the new storage box without turning them off," he said. "We have very specific SLAs [service level agreements] and can't tolerate hosts going down for any significant length of time."
"How can we do lease expiration on our hardware if there's a lockin to the hardware for the life of the application?" he said.
He's not the only user confronting this issue. "For now, we think VMware is great for server consolidation, but it really only works locally," said Chris Macsurak, storage administrator for MWH Global.
"It's a whole process to get data from one VMware system to another," he said. "We have to replicate the data, reformat the server to be the same as the first one and then bring VMware back up."
Tom Becchetti, senior infrastructure engineer for MoneyGram International and the featured speaker during the afternoon's sessions on VMware recovery, agreed. "Right now you need a separate migration tool to get data off the back end, and even third-party VMware hot backup tools require a reboot," he said.
Users said they were waiting to see if VMware version 3.0, due to be released at the end of this quarter, would contain the capability.
VMware spokesperson Amber Rowland declined to comment on what would specifically be supported in version 3.0, slated for release at the end of this quarter, but said, "This is an interesting direction that VMotion can go. It doesn't support [live data migration] today, but a cold migration can be used to move a virtual machine from system to system, and it only takes a few minutes."
Analysts say that won't cut it for most shops. "In this day and age when nondisruption is a prerequisite, no one in their right mind would just unplug one storage box completely and come back the next day with another one," said Arun Taneja, founder and consulting analyst with the Taneja Group. "Any migration to new storage will be gradual -- and users can fake VMware into thinking that the new system is the same after they migrate the data.
"But," he said, "it would be a two-step process."
Jancewicz said he is considering a two-step process of his own: installing IBM's Storage Volume Controller (SVC) between his servers and back-end storage so that the VMware servers never know the difference between back ends. VMware's parent company, EMC Corp., also offers a storage virtualization product, called InVista, but Jancewicz said he felt SVC is more mature, and that he generally prefers IBM.
"But it is ironic," he said, "that I'm using a product from an EMC subsidiary, but right now it'll mean more of my money will go to IBM."