Backup Instant Recovery Types: The Evolution of RTO
Instant recovery – also called failover virtualization or virtual failover – is a big deal these days. What these technologies allow is a faster RTO (Recovery Time Objective) by using virtualization to accelerate the recovery. The term “instant recovery”, of course, is a marketing term – in fact these typically take at least a few minutes to spin-up.
There are two basic types of instant recovery. One works inherently with virtualization protection – and by that I mean protection with technologies such as VMware, Hyper-V, XenServer, Xen, KVM, etc. What these do is to allow the data that has been backed up from a virtual host-level server to be used to quickly boot a replacement virtual machine (or virtual machines.) Typically this type of instant recovery is used in virtualization environments which require higher availability than is typically found on a backup system.
The other type of instant recovery occurs when virtualization is used within a backup software (or backup appliance) such a non-virtualized operating system (or a virtualized operating system at the guest or virtual machine level) such that the operating system and its applications may be started within the backup software (or backup appliance) itself. The “spinup” of the virtual image thus doesn’t require another computer with virtualization software installed in order to perform the instant recovery. In the past this type of instant recovery has been used in environments that haven’t implemented virtualization.
From the buyer perspective, the advantage to the ability to “spinup” the virtual machine on the backup server (or backup appliance) is that you don’t need to implement virtualization and you have less non-utilized hardware. From the backup vendor perspective, it’s difficult (not impossible, but difficult) to handle all of the tasks associated with modern backup (e.g., compression, encryption, metadata processing, granular restores, deduplication, replication, etc., etc.) and also handle “spinup” instant recovery on the backup server (or backup appliance) itself.
There are a few vendors out there today who have both types – instant recovery for virtualized environments and for non-virtualized environments. It’s a good idea if you’re evaluating your backup strategy to understand what your current and future needs are with respect to RTO and instant recovery technology.