Troubleshoot slow backups

[jinxnbu]

Hi 

I have an AIX netbackup envt with db2 backups some which are san media servers and others just clients.

I wnat to check  logs which i can look at and also tuning parameters in order to try and improve backup speed.

From Media server i know i can check teh bptm logs. Any other logs that will provide insight and what are the tuning parameters I can look into ?.

Thanks in advance.

[sdo]

This document is probably the best place to start:

https://www-secure.symantec.com/connect/forums/updated-netbackup-backup-planning-and-performance-tuning-guide-release-75-and-release-76

[Nicolai]

Performance tuning can be a long lasting search

However the Symantec NetBackup Backup Planning and Performance Tuning Guide Release 7.5 and Release 7.6 has a hole chapter dedicated for performance tuning.

http://www.symantec.com/docs/DOC7449

Have you tuned NUMBER_DATA_BUFFERS / SIZE_DATA_BUFFERS ?

What is the backup media - tape or disk

What version of Netbackup are you runnign ?

[jinxnbu]

Its AIX San media server running 7.6.0.4 and the backup media is VTL.

I have tried the following values

262144 SIZE_DATA_BUFFERS

128 NUMBER_DATA_BUFFERS

[jinxnbu]

will creating the NOSHM file help to improve performance ?

[Nicolai]

not that I am aware off.

Please also take a look at GEN_DATA in this tech note

http://www.symantec.com/docs/TECH75213

GEN_DATA will help you identify where the problem is located. 

The  idea : 

• run GEN_DATA to VTL - what value do you see
• Create a null disk device - what value do you see
• Run GEN_DATA from the client - what value do you see.

By separating the entire string from client to VTL it should help you find the link that not performing.

Please remember - I can only guide you. There is no blue box to checkmark that will let you run backup 3 times faster.

[Michael_G_Ander · Accepted solution]

I would also look into tuning for the AIX OS it self, if you are running the AIX Clients in PowerVM  the VIO Server(s) is the place to start. We ran the Vioadvisor regularly to get indications of what might be improved.

nmon on AIX can show things like CPU, disk i/o, adapter i/o and so on.

Being db2 backups also look in the db2 documentation for backup parameters.

When doing performance tuning always start with finding out what the theoretical limits on the different pieces of infructure like SAN adapters, disk systemer as that will give you an idea of what you can expect. In general I have found, you max get around 80-90% of the theoretical limits on a tuned system.