Some quick thoughts on using server virtualization for disaster recovery. The key metrics in using VMs for DR is RTO and RPO. These are defined during the BIA process. One question that I wrestled with was how to get a near time RTO (within minutes before the disaster) and a rapid RPO (within 1hours after the disaster).
Traditional P2V techniques rely on a live system or a nightly backup, so RTO is up to 24 hours. Traditional P2V also relies upon writing the data back out into virtual disks, so the RPO for our average server was up to 7 hours. We addressed these challenges by keeping the storage on a backend SAN and pointing the disk into the VM in the event of a disaster. The RTO is then near time and the RPO is an hour or less.
The DR strategy requires native NTFS disk access and SAN support. Both VMware ESX and Hyper-V support this type of DR. Linux based hypervisors such as Xen do not.
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