Backup starting fast - then gets incredibly slow!

[beistrich]

Hello!
I have again a strange problem with veeam. It is the first backup, so veeam performs a full backup.
The backup starts with about 90Mb/s but then becomes steadily slower - ow it stands at 2 - 5 Mb/s

It says the bottleneck is the target (87% at the moment, but now ap 99%). But this is strange, because the backup process becomes slow only later - approximately after the 2nd vm (of 13!)

This is the graph:




Somebody has an idea - Its VB 7 Patch 3

[foggy]

Christoph, have you monitored CPU and memory usage on the proxy during the backup? Here's an old but useful thread regarding similar issues, should give you some thoughts.

[beistrich]

Hi!
CPU of the Proxy is less than 20%...
Also tried to reset "CBT" - also doesn't help.
Any other Idea?
Should I try disabling indexing?

[foggy]

What if you try to backup to some other storage to check whether the storage is the actual cause of this slow down?

[beistrich]

It is not the storage I think.
When I back up a single VM the speed is normal.
When I create a backup job with multiple VMs it is very slow! (1 VM at a time) - using vCenter Server Appliance.

[tsightler]

Can you tell us something about the backup storage? Is it a NAS?

[beistrich]

Yes its a NAS (Qnap) with 12 TB (4*4 TB RAID5)

Backup settings:
1 Concurrent task
Lan Target
CBT activated
NBD
VSS activated (no indexing)
Veeam connects through vCenter Server appliance.
VMs are chosen selectively

[veremin]

With one concurrent task, there should be no difference between job with one or multiple VMs, as only one VM can be processed at any given moment. If I were you, I would still try to backup to different location in order to exclude target storage from list of suspects. Thanks.