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Staying in sync
"With pressure on businesses to respond more quickly to customer demands, the IT infrastructure supporting the business changes on a daily basis," says Bob Laliberte, an analyst at Enterprise Strategy Group (ESG), Milford, MA. "So any DR environment that was implemented and tested on day one could be at risk on day two. Unfortunately, that risk isn't discovered until a copy of the backup is needed or a DR test is run."
Jeff Pelot, chief technology officer at the Denver Health Hospital and Medical Center, saw how a seemingly minor change in the backup environment can cripple a DR effort when one of his LeftHand Networks Inc. IP SANs failed to take over for another during a monthly DR test. "LeftHand was migrating from their iSCSI initiator to Microsoft's [iSCSI Software] Initiator ... and I guess we found a bug," he says. Pelot says he's now "fairly comfortable" his systems will work as needed, but he admits that "what I don't know is what scares me"--that any update by any vendor's product might introduce a similar bug that could crash his DR systems. For that reason, his staff carefully evaluates which upgrades are critical
| and applies them to one system in a cluster at a time to ensure they work before installing them on the other system, he says.
Many storage shops only maintain a knowledgeable staff at their production site and not at a DR site, says Dan Lamorena, senior product marketing manager at Symantec. That makes it harder to ensure that no critical data is lost during replication, he says, and that the proper volumes and LUNs are configured in the right way at the DR site.
This was first published in May 2008