Slow Backups and Fast Restores

[Denzo]

I have W2K3 Master/Media Server running NBU 6.5.5.  I backup over the LAN with 1Gbps Ethernet. My backups are extremely slow and do not go over 5mbs. Strangely, though, my restores are fast at about 45mbs. Has anyone experienced the same problem? Please assist.

[RiaanBadenhorst]

Hi Denzo,

What are your multiplex/multistream settings, do you backup a lot of clients together to a bunch of drives, or one client per policy etc. You should take into account that if you're running backups you should look at the aggregate speed (all the backup jobs active at one time) rather than one backup job.

When you're restoring its obviously running by itself.

You can also break down the performance by checking each components/stage of the backup i.e. how fast the data can come from the client's disk, how fast it can be transferred across the network, and finally how fast the data can get on tape once its on the master. This will highlight bottlenecks.

R

[Denzo]

hi Riaan,

I am running one backup at a time and still won't go beyond 5mbs.

[RiaanBadenhorst · Accepted solution]

You can do the following for file system backups

Test the clients ability to read from its own disks with "bpbkar -nocont". It simulates a backup process but sends it to dev null. bpbkar -nocont D:\Temp > NUL 2> NUL

Please check the syntax for your specific OS. For windows you can open the job tracker to see the speed of the backup, for unix based create the log bpbkar log files and check the speed in there.

Check the network speed with FTP/Copy from the client to the master.

Check the speed of your tapes drives by backing up similar dataset located on the master server. Also check the speed you can achieve on the master's disk using bpbkar -nocont.

This will show you where the bottle neck is.

R

[Marianne]

Try to test nework copy without NBU:

Either normal network copy or ftp.

Also test read speed from disk (source data could be heavily fragmented). Test utility can be downloaded from http://www.hp.com/support/pat

Another possible cause is TCP Chimney:

http://www.symantec.com/business/support/index?page=content&id=TECH60844

Failures are not always seen, just slow backups. I have personally witnessed increased performance by disabling TCP Chimney.

[Marianne]

Riaan was a bit faster than me...

I've been experiencing problems with bpbkar test lately - seems to be broken in Windows clients since version 6.5. I've used it many times in the past - worked fine when I tested it on a version 5.1 client recently (that is when we discovered the TCP Chimney issue).

BTW - check TCP Chimney on server as well as clients.

[Yasuhisa_Ishika]

"Collect True Image Restore Information" feature sometimes affect backup perforce .