Generally people try to tune DB2 backup by manipulating PARALLELISM parameter but there is no need to manipulate this parameter if you are looking for a least possible time to backup the database. Let DB2 figure out the optimal value for you for PARALLELISM.
But, you should consider following to increase the backup speed.
- Backup on multiple physical disks simultaneously.
db2 backup db sample to /mnt/bkp1, /mnt/bkp2, /mnt/bkp3 etc. and there will be different backup images created with extensions such as .001, 002, .003 etc. This will give you the fastest performance.
- Make sure that your UTILHEAPSZ is large enough.
- Make sure that the backup mount points are on physical drives. Beware of your SAN volumes if you do not know how they are mapped to the physical devices.
- Do not try to tune PARALLELISM and let DB2 figure this out
- WITH num_buffers BUFFERS. Use num_buffers as much as you can since you are taking backups on multiple locations.