TSM DB Restore takes excessive amount of time

[djwaddell]

Hi - Hope someone can help with this query...

Basically - TSM DB takes 20-30 minutes to back up but I'm seeing restore times of 3 - 4 hours.

Background -
The TSM DB Backup normally takes 20-30 minutes - according to recent posts in this forum, I should expect the restore time to be around 1.5 x the backup time... and certainly at a recent DR test the consultant we had restored the DB in around 1 hour.

I've been attempting to test the DR restores for myself (prior to further DR Tests) and at my first attempt it took 2 hours to restore the DB and a further 2 hours to complete the log restore.

We've removed a lot of old backup data recently (we've moved off 3590 tapes) and have seen the DB cut down to 30GB in size... and the DB backup times cut to 20 minutes - but when I attempted another restore at DR it took 3 hours and 15 minutes.

Question -
How would I cut down the time taken to accomplish the TSM DB Restore?

(Can anyone suggest what the consultant might have done that resulted in the DB restore completing so much quicker).

TSM is 5.4.2 on AIX 5.3 - The tape drive used in both cases was LTO3, fibre connected to the TSM Server.

Thanks in advance.

 

[chad_small]

Did you use raw volumes? Also are you doing a roll-forward or p-i-t restore? P-I-T's take less time and using RAW can speed up the process (not necessarily make it quicker to restore the data, but quicker in getting the DB back up once the DR test starts). The disk type matters too. What type of disk are you using?

 

[djwaddell]

I'm just using the command:

dsmserv restore db todate=today preview=no

The TSM Server is an IBM p615 and the DR box is a p505 - The production TSM DB is on a DS4300 enclosure whilst the DR restore uses internal disks.

 

[BBB]

What kind of storage are you restoring to and how big is your DB and logs?

 

[djwaddell]

Sorted

Sorted now. Turns out this was due to using a tape backed up using a LTO4 Drive and then restoring using a LTO3 Drive. I had thought the LTO4 would have taken account of the fact that all tapes are LTO3 but it turns out not to be entirely the case.

I've now set the Device Class of the LTO4 Drive to specifically write in LTO3 format.