In my previous blog Not all Veeam Instant Recovery processes are equal. I alluded to the fact I would be talking about another Instant Recovery option that we use being a “Instant Disk Recovery”
This feature is pretty self-explanatory in the sense that with Instant Disk Recovery, you can immediately restore VM disks from a backup file and publish them in the initial format.
We use Instant Disk Recovery when we need to:
- Recover VM disks, not an entire VM.
- Recover VM disks and keep the target VM (to which you want to attach recovered disks) turned on.
So how does it work you ask. Veeam Backup & Replication performs the following steps to recover disks:
- Checks whether the vPower NFS datastore is mounted to the ESXi host and contains VMDK files of the recovered disks.
- (If you replace an existing disk) Unmounts and deletes the existing disk.
- Connects the recovered disks to the target VM.
- Initiates a creation of a protective snapshot for the target VM. If Instant Disk Recovery process fails, the protective snapshot guarantees no data loss.
- Writes changes made to the recovered disks to redo logs on the vPower NFS server.
What sorcery is this Veeam vPower NFS Service?
The key construct of the vPower technology is the vPower NFS Service. The vPower NFS Service is a Microsoft Windows service that runs on a Microsoft Windows machine and enables this machine to act as an NFS server.
On the vPower NFS server, Veeam Backup & Replication creates a special directory — the vPower NFS datastore. When you start a VM or a VM disk from a backup, Veeam Backup & Replication "publishes" VMDK files of the VM from the backup on the vPower NFS datastore. Technically, Veeam Backup & Replication emulates the presence of VMDK files on the vPower NFS datastore — the VMDK files themselves are still located in the backup file in the backup repository.
The vPower NFS datastore is then mounted to the ESXi host. As a result, the ESXi host can "see" backed-up VM images with the help of the vPower NFS datastore and work with them as with regular VMDK files. The emulated VMDK files function as pointers to the real VMDK files in the backup in the backup repository.
The Instant Disk Recovery feature sure has come in handy, and with being so quick and easy to do, we are able to get customers backup up and running pronto.