If you replicate a VM to a remote DR site, you can use replica seeding. Replica seeding helps significantly minimize the amount of traffic going from the production site to the DR site over WAN or slow LAN links.
With replica seeding, you do not have to transfer all of VM data from the source host to the target host across the sites when you perform initial replication. Instead, you can use a VM backup created with Veeam Backup & Replication as a replica “seed”. When the replication job starts, Veeam Backup & Replication will use the seed to build a VM replica.
Replica seeding includes the following steps:
- As a preparatory step for replica seeding, you need to create a backup of a VM that you plan to replicate.
- The created backup should then be copied from the backup repository in the production site to the backup repository in the DR site. After the backup is copied to the backup repository in the DR site, you will need to perform rescan of this repository, as described in the Managing Backup Repositories section.
- When you create a replication job, you should point it to the backup repository in the DR site. During the first run of a replication job, Veeam Backup & Replication accesses the backup repository where the replica seed is located, and restores the VM from the backup. The restored VM is registered on the replication target host in the DR site. Files of the restored VM are placed to the location you specify as the replica destination storage.
Virtual disks of a replica are restored from the backup as dynamically expanding.
- Next, Veeam Backup & Replication synchronizes the restored VM with the latest state of the original VM. After successful synchronization, in the Home view of Veeam Backup & Replication, under Replicas node you will see a VM replica with two restore points. One point will contain the state of the VM from the backup file; the other point will contain the latest state of the original VM you want to replicate.
- During all subsequent runs of the replication job, Veeam Backup & Replication transfers only incremental changes in a regular manner.
Replica seeding dramatically reduces traffic sent over WAN or slow connections because Veeam Backup & Replication does not send the full contents of the VM image. Instead, it transmits only differential data blocks.
If you add new VMs to an already existing replication job, you can enable replica seeding settings for these VMs. In this case, the newly added VMs will be seeded from the selected backups at the next pass of the replication job. VMs that have already been processed by the job by the time you add new VMs will be processed in a regular manner.