Difference in backup processing rate

[peters.]

We are running BR 8.0.0.2084 to backup few windows 2008 VM's in a chain, one after another (not in paralell). All VMs are stored on the same Dell MD3400 datastore.

One VM incremental backup is being processed with rate:
16. 6. 2016 21:49:09 :: Hard disk 1 (50,0 GB) 1,3 GB read at 4 MB/s [CBT]
16. 6. 2016 21:49:31 :: Hard disk 2 (100,0 GB) 21,4 GB read at 11 MB/s [CBT]

while another
16. 6. 2016 22:39:46 :: Hard disk 1 (50,0 GB) 1,7 GB read at 44 MB/s [CBT]
16. 6. 2016 22:40:13 :: Hard disk 2 (125,0 GB) 2,8 GB read at 17 MB/s [CBT]
16. 6. 2016 22:41:04 :: Hard disk 3 (40,0 GB) 643,0 MB read at 57 MB/s [CBT]

Used method is "Using backup proxy VMware Backup Proxy for disk Hard disk [hotadd]".
The "Enable storage latency control" is disabled.

Is there something obvious which can be causing such a big difference in the processing rate? I was thinking about disk type: Thick vs Thin provisioned, but the second server has disk=thick lazy zeroed, disk2&3 are both thin. First server is thin.
Both VMs are on the same ESXi 5.5.

Thanks,
Peter

[PTide]

Hi,

Have you tried to swap the jobs' start time and compare the stats again? I susupect that some other activity is taking place at the storage somewhere close to 21:40-21:50. Also, have you considered upgrading VBR to the latest version?

Thanks

[peters.]

Thanks I'll try that and let know the result