BE2010 / VMware Agent: Backups get slower the longer a job runs
I've noted this very odd behaviour of BE2010's VMware Agent. I'm backing up VMs via the 'san' mode (from our EMC SAN) to another Disk Drive and my jobs usually start off with fabulous speeds at around 3500MB/min.
However, the longer the job takes, the slower the speed gets. The speed gets "resetted" once the backup of one VM (or I believe even a Harddisk of a VM) is done. It seems like for every vmdk-file, the backup rate starts off being very fast, and then gets constantly slower until the disk is fully backed up. Also, the CPU load gets higher and higher on the BE Server the longer the backup jobs runs.
This is hardly noticable on smaller VMs (up to 100GB disks)... However, we have a file-server with a 1TB VMDK... speeds start off at 3500MB/min, and towards the end, the speed is down to 150MB/min (not on average, but the Byte Count just clocks up about 12MB every 5 seconds, so do the math), with beremote.exe using up once processor completely.
The BE-Server is a HP Proliant DL380 G4 with two Xeon 3.6GHz (Hyperthreading, but no mulicores). The target device is a regular B2D Folder (not a dedupe store).
The issue obviously has something to do with the vmware agent, as regular backups via the windows agent of the same VM start off slower, but are being backed up at a constant speed of 800MB/min.
I read in the VMware forums that this might be because VCB (which is not used by Backup Exec 2010 with vSphere and not installed, but I guess the behaviour is still the same with the VMware StorageAPI) uses a compression per default, which would explain the slower backup rates and the higher cpu load the longer the job lasts. Via VCB, it is possible to disable this compression. I could not find any option in BE2010 for this though, except of disabling the compression at the job level (which i did, but it did not change my backup speeds).
Is anyone else having this problem? Do you have a workaround or solution?
Thanks and best regards,