By Eric Siebert
Using virtualization technology as part of your disaster recovery (DR) plan has some great benefits, but there are also related challenges and costs. It's often assumed that server virtualization technology will save lots of money on server hardware. Lower operational costs will save money in the long run, but you'll have some additional up-front costs in addition to new physical servers.
For example, using two or three physical servers with virtualization at your disaster recovery site in place of eight to 10 physical servers at your main site will obviously reduce hardware costs. But you'll have to consider the cost of virtualization software, management and data protection applications.
If you're already using virtualization at your main site, using it at your disaster recovery site is an easy decision. If not, expect a learning curve in understanding how to properly implement, configure and manage it. Also, virtual machines usually require management and backup applications designed specifically for virtualization that may not work with physical servers. So, you might need separate tools for virtual and physical environments, which increases costs and management complexity. Some applications, like Microsoft System Center, can manage both environments via a single interface; similarly, Symantec Corp.'s NetBackup can back up both environments.
There are some clear advantages to using server virtualization at a disaster recovery site. Disaster recovery rack space is often expensive and with fewer racks your ongoing costs will be lower. Fewer physical servers also mean fewer network port requirements and less gear to maintain. You can also replicate virtual machines running on hosts with shared storage at your main site to hosts with direct-attached storage (DAS) at your disaster recovery site, which can result in more savings. Server virtualization allows physical hardware independence, so you can use any type of server hardware at your disaster recovery site without having to worry about operating system and application compatibility.
Part of this guide was originally published in Storage magazine.