Slow TSM image backup to Data Domain

[Ches]

Hi all, I've enjoyed reading these forums for some time, but have now registered finally, and here's my first post.

We have TSM 7.1.1 on AIX backing up a number of node images to a Data Domain - currently the backup is running at around 6MB per second. Backup runs over NFS on a 10GB port.
Last month, we upgraded to 7.1.1 from 6.2 and prior to the upgrade, these exact same backups ran at around 45MB per second.

Nodes that Backup-to-tape and backup-to-disk seem unaffected, but Data Domain backups have slowed down by around 75%. Has anyone else had experience of this? I'm baffled as to why only the DD has issues. Also, test of write directly from TSM AIX server to the Data Domain show no slowdown.

Looking forward to hearing your thoughts,
Ches

 

[moon-buddy]

You might need to tweak the estimated capacity for devclass=file. Increase or decrease the value to find a sweet spot.

There might also be a driver (AIX side akin to TSM 7.1.1) or a DDOS issue in-line with TSM 7.1.1. Reach out to IBM and/or EMC.

 

[umur]

Do you use DD as a VTL or as NFS?

 

[Ches]

Just to close this off if anyone else gets a similar issue - our problem was that after upgrade to 7.1 the RAM in the server was insufficient. After doubling RAM, the backup performance increased dramatically.