Rapid Recovery, Virtual Standby
In this blog post, I’ll discuss some issues pertaining to Dell Data Protection | Rapid Recovery virtual standby machines.
Rapid Recovery is a solution that backs up volumes at the block level, meaning the backup results are volume images. These images can be mounted as physical disks for file restore on the Core (backup server), or on any other computer when using the Local Mount Utility application for Rapid Recovery.
Recovering physical servers is more challenging. Data volumes can be restored on spare volumes or raw disks attached to any machine that has the Rapid Recovery agent installed. However, if the system drive of a crashed physical server needs to be recovered, a bare-metal recovery (BMR) operation is needed. This means the machine needs to first boot from a boot disk, and the system drive is restored the same as a collection of data volumes.
So, what happens if you need to have a server running, but it crashes due to faulty hardware and you don’t have a spare physical server ready for deployment? That is simple: Export the desired recovery point to a virtual machine (VM). In practice, the process is similar to a BMR or even a data volume restore. Rapid Recovery makes the process simple by supporting quite a few hypervisors, chief among them VMware ESXi/vCenter and Microsoft Hyper-V. The hypervisor creates the VM, Rapid Recovery restores the system volume and any data volumes that may be needed, and then the process is finished by modifying the newly created virtual system drive to allow the VM to boot.
The next logical step is to have a few critical protected servers exported in such a way that, if they fail, a VM (already created as shown above) is prepared to replace them. That is a virtual standby. To accomplish this, a new export is performed after each backup. If the newest backup snapshot was an incremental, meaning that only the data that differs from the previous backup was transferred over the wire, and this new backup is merged with the virtual standby, then the export process will not be resource intensive. If all goes well, the virtual standby is in sync with the newest backup.
It goes without saying that this is a generous, almost seductive concept. If paired with the fact that virtual standby machines can be spun up at the disaster recovery (DR) site (where data is replicated), it means that theoretically, in case of catastrophic failure, it’s possible to recreate the whole local area network at the DR site (or even in the cloud) and have users work remotely with minimal interruptions. Little wonder that virtual standbys are a cornerstone of each DR plan and — I say it based on personal experience — literally haunt the dreams of many backup administrators!
From a backup perspective, critical machines are the ones that contain valuable data. From a virtual standby perspective, the critical machines are those that assure the network infrastructure.
In the end, it’s the job of our organization to prepare the best DR strategy specific to our clients’ goals. Rapid Recovery offers a lot of flexibility in choosing the best combination of features that allow balancing both performance and costs. Among these, if used properly, virtual standbys have a place that cannot be underestimated.