Database backup cron job consumes large amount of memory and doesn't
free much up after the backup's complete.

We're running DB2 9.1.0.4 on AIX 5.3

We recently implemented a new system into a Production environment.
Users don't have access yet. Our system guys noticed a large increase
in memory usage at 5:00 am the other day, the same time that a cron
job starts the db backup. The memory usage didn't reduce
significantly after the backup completed. The jump in memory usage
was about 1.2 Gb. The database is about 500Mb in size. When we
recycled the instance, the 1.2 Gb was freed up. The next morning
(5:00) the memory usage jumped again. I'm the development DBA, so I
don't have access to Production to look at anything, but I can request
any info of interest.

Any idea why we'd see this behaviour?

Thanks.