Backup & Replication 4.0 Replication Snapshots

[crazycommando]

Hi.

I am new to Veeam and just been testing out Backup & replication 4.0
Quick question.
The documentation states: "Unlike competitive solutions, Veeam Backup & Replication does not require that replicated VMs run with open snapshots that prevent Live Migration and DRS."
I have found there is always an open snapshot while the replication job is taking place.
My replication job is a XP VM between 2 ESX 4.0 hosts connected over a VPN (using vStorage API Network mode)

Thanks

[vbussiro]

The snapshot is open during replication indeed, which should be quite fast considering usage of vstorage API. So most of the time, you are not bothered by a snapshot.

[Gostev]

Correct. DoubleTake or Vizioncore require that the source VM runs with open snapshots all the time (both periodically replicate the snapshot files to target, and merge them into the replica VMDK). With Veeam however, VM has snapshot for only few minutes (during each replication cycle), so most of the time, VM remains "clean".

Having snapshot open all the time obviously also requires a lot of disk space on source, and affects VM performance, especially during snapshot management procedures. Imagine periodic daily replication, every day there is a need to commit the snapshot to source the VM, and snapshot can grow very large for 24 hours.

To be fair, besides all the above-mentioned drawbacks this mode has certain benefits too on ESX 3.5 (faster incrementals comparing to Veeam v3 approach). But with vSphere and Veeam v4, our incrementals became are comparable and even faster due to the ESX4 changed block tracking.