Very slow Exchange restore performance

[keyz]

Hi,

i have a big problem restoring Exchange databases. Here is our configuration :

- 1 master server Netbackup 6.0 MP7 on AIX 5
- 1 VTL (falconstor)
- 1 media server Netbackup 6.0 MP7 on Windows 2003 server, attached to SAN with dedicated virtual and physical drives
- several Exchange clients with mapped disks attached to SAN

Performance backups are very fine but when we try to restore some exchange banks the performance are very very poor and not stable. Sometime it will restore great for 5 minutes, then nothing for 5 or 10 minutes, then restore again... ...

I tried a lot of things (increase buffers, disable tcp offload, update NIC and  HBA drivers) but i'm desesperate. Maybe it's a problem with the SAN communication ? How can i debug this ? maybe activate some log... ?

I'll appreciate any idea :\
Thanks in advance and sorry for my bad english

[Gerald_W__Gitau]

First things first, the buffer settings are they the same as when you did the backup? Whats the backup throughput and what is the restore throughput? Is the backup going straight to tape or via VTL? Is multiplexing enabled?

[keyz]

Buffers settings are the same as when i did the backup.

For example this afternoon i backuped a 50 GB Exchange bank in 25 minutes. The backup goes to VTL first. 

Multiplexing isn't enable.

[keyz]

On bptm log i have plenty of this errors :

tape_error_rec: absolute block position after read position is 1716515
read_data: ReadFile returned FALSE, The request could not be performed because of an I/O device error
read_data: attempting read error recovery, err = 1117

Could it be it ?

[Deepak_W]

From the bptm log I suspect that this is replated to the hardware you are having.

Look into below mentioned TN for more details on the same.

http://seer.entsupport.symantec.com/docs/293070.htm

This will help you troubleshooting the same.

Hope this will resolve your issue.

[keyz]

Thanks for your response.

I don't understand how it can be an hardware error.
When i try to restore datas are still on virtual tapes (so on san disk) so what could it be ? hba card ? san disks ? cables ?

I found a symantec note saying that STOR miniport driver is not recommended for Netbackup. I downgraded to SCSI miniport but we have same effects

I'm desperate...