Slow Backup Speed

[Bkp2020]

Database Backups running slow at 3 Mbps Speed and How its speed can be improved. Its running Backups on Data Domain and Pure Disk.

[Marianne]

Please tell us more about this Client. 
OS, DB type and version, NBU version.

The reason for my question is because troubleshooting should start on the client.

Poor performance could be due to poor disk layout, poor database layout, system resources on the client, etc...

Ask dba if a db backup can be tested to /dev/null. 
This will test read speed from db.
If there is non-db data on the same filesystem/disk, the 'bpbkar' test can be done to 'null' device to test disk read speed without db inbetween. See http://www.symantec.com/docs/HOWTO56131 

If disk read speed is fine, the next test will be network.
ftp a file of +- 1GB in size to media server.

Chances are that problem will be in one of above areas.

[Linette_V]

There are many different things that could be causing the slow down. To narrow it down I'd recommend reviewing the following article:

Overview of NetBackup performance testing: http://www.symantec.com/docs/TECH147296 (the links at the bottom of this document are good too).

Then check out the performance tuning guide (even though it's 7.1 it has good a currently relevant information) http://www.symantec.com/docs/DOC4483

Good luck!

[Bkp2020]

NBU Version 7.5, OS AIX 5.3,  DB Type Oracle 11g.

[Marianne]

First step is to find the bottleneck.

Here is an excellent article with information on how to identify the bottleneck and performance tune rman:  http://dbasolutions.wikispaces.com/RMAN+Performance+Tuning

More links in this post: https://www-secure.symantec.com/connect/forums/oracle-db-performance-hit-during-daily-full-backups

[Michael_G_Ander]

If you are running the AIX inside a PowerVM LPAR, then disabling the offload to the netcard can improve the network transfer. It is counter initiuve untill you remember the LPAR is virtual

You say the database backup is slow, have the rman script being tune for throughput ? number of channels, number of concurrent read datafiles and so on

To see how fast you can get data out the database, get rman to read only, think the rman option is backup validate

What is the connection between the client and the media server ? and it is shared with other clients at the time of this backup

[Yasuhisa_Ishika]

Please tell us your DB size and backup image size. Typically if backup image size is too small, throughput in NetBackup side can be too low. In RMAN backup operation, Oracle scans all the blocks in DB files for block health check even if blocks has not assigned to data, and then Oracle only passes contents of assigned blocks  to backup channels. So if assigned blocks is too few, too small data is paased in time of scanning.  Backup throughput in such case shows too low, but ithere are nothing wrong in both Oracle and NetBackup.

Please check size of DB files and backup images.