VCB SAN backup -> speed is slow

[tig3rclaw]

At a customer site we are experiencing slow speeds when we are using VCB backup via Veeam (Backup 4.0)

However when we do a VCB backup with the command line, then this customer gets nice and proper speeds.
What can be the cause of this?

Does anyone have any ideas?

[Vitaliy S.]

Hello Martin,

Do you use the same VCB command that we are using (it can be found in the log files)? If you cannot find it, please email our support team (support@veeam.com) with the job log from Help->Support Information and they will help you to locate it.
Also it'll be great to hear more details on your infrastructure, have you used the same target storage for Veeam job and just VCB? Can you tell me please what figures do you experience?

Thank you.

[Gostev]

However when we do a VCB backup with the command line, then this customer gets nice and proper speeds.
What can be the cause of this?

My ideas:
1. Weak CPU on Veeam Backup server (compression).
2. Target storage issue.
3. Not using the same VCB command as Veeam Backup uses.

Also, I recommend switching to vStorage API SAN mode instead of VCB.

[tig3rclaw]

My ideas:
1. Weak CPU on Veeam Backup server (compression).
2. Target storage issue.
3. Not using the same VCB command as Veeam Backup uses.

Also, I recommend switching to vStorage API SAN mode instead of VCB.

Why do you recommend to switch to vStorage API SAN?

Shouldn't VCB be faster then vStorage API SAN?
VCB is using the fibre connections to the SAN.

[Vitaliy S.]

Hello Martin,

Basically, VMware vStorage API is as a replacement for VCB (however we still support both VCB) and with vStorage API SAN mode VM data is also retrieved directly from FC/iSCSI shared storage (SAN), providing LAN-free transfer of VM data.

We've seen perfomance increase at many of our customer's sites, so vStorage API is the single best choice for ESX(i) 4 hosts, as well as for ESX(i) 3.x hosts in case you have shared storage. vStorage API mode will provide better performance all around comparing to other processing modes.