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NetBackup 6.5 slow backups over network

Created: 10 Dec 2013 • Updated: 21 Jan 2014 | 4 comments
This issue has been solved. See solution.

I am configuring a NetBackup 6.5 installation. Here is the topography:

Master server: windows 2003 R2 x64

client: windows 2003 R2 x64

client: NetApp over NDMP

The policies are configured with zero overlap in the start times. The number of data buffers is 16. We are running with no shared memory. The size of the data buffers was set at 256 KB, but this was removed to increase performance.

The master server backs up at 45 MB/s. The other windows client backs up at 100 KB/s. The logs in the Activity Monitor do not indicate any problem with either backup and there is no dwell over any open file. A rough copy test initiated from the master server was able to push 36000 KB/s back and forth between the master server and the client. Does anyone have a suggestion for improving the performance?

Thanks,

Jeff

Operating Systems:

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Mark_Solutions's picture

You know the first thing i am going to say ... 6.5 is long end of life - please try and upgrade so that you can get some sort of support if we cannot help you on here

Is this a backup to disk on the Master Server?

If so then i would suggest the databuffer used are:

NUMBER_DATA_BUFFERS_DISK = 64

SIZE_DATA_BUFFERS_DISK = 1048576

This does depend on the amount of memory in your Master Server though

There are similar settings for NDMP data buffers but i have an idea that there is an issue with using these in 6.5 - will see if i can spot the tech note

Try these and see how it goes - if going to tape you need different settings dependant on the tape type

Your network is also a potential bottleneck

Authorised Symantec Consultant

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Marianne's picture

Totally agree with Mark - UPGRADE!

First thing you need to do is to determine client's ability to read data from disk.

See:
How to benchmark the performance of the bpbkar32 process on a Windows client 
http://www.symantec.com/docs/TECH17541

Let us know the result.

Next, turn off TCP Chimney on W2003 servers and clients:
http://www.symantec.com/docs/TECH60844

Supporting Storage Foundation and VCS on Unix and Windows as well as NetBackup on Unix and Windows
Handy NBU Links

jeffcopes's picture

Thanks for the very quick reply to my question.

The backups are going to tape. NUMBER_DATA_BUFFERS is set to 16 and SIZE_DATA_BUFFERS is left to default though at one time we tried setting it to 262144 (256*1024).

We did benchmark the performance of bpbkar to be 17 MB/s, but that was before other tuning and this must be different since we are seeing twice that speed backing up the master server. When I am back out tomorrow I will re-run that test to see what it and will also disable TCP Chimney.

A straignt DOS copy over the network using hostnames (\\servername\c$\temp) gives us 36000 KB/s, so the network connection between the master server and this client does not seem suspect to me.The master server and client both have 12 GB memory.

We have been reluctant to upgrade since in our case the cost is pretty high. We are possibly going to migrate to Backup Exec since the system is very small and we only have the requirements to backup WS2003 to tape and NetApp to tape.

Thanks,

Jeff

Marianne's picture

We did benchmark the performance of bpbkar to be 17 MB/s.

This points to a read problem on this specific drive letter/filesystem. The reason can be anything from busy filesystem, antivirus scanning files being accessed (backed up), bad fragmention, to poor lun layout.
There is nothing that can be done from NBU to make this any faster.

Focus troubleshooting on the specific drive letter on the client that is experiencing poor backup performance.

Better overall performance can be achieved if you enable multistreaming to backup more than one drive letter simultaneously.
 

Supporting Storage Foundation and VCS on Unix and Windows as well as NetBackup on Unix and Windows
Handy NBU Links

SOLUTION