Oracle RMAN High Paging on AIX - Slows AIX Server Response
Posted on 2010-01-07
Some backup info first:
We have an IBM RS6000 9131-52A that uses a DS4800 array.
We have 3 diskgroups: rootdg, datadg, and backdg.
datadg is used to house our Oracle database.
backdg is used to house our Flash Recovery Area.
There are 6 Oracle databases running on this server. Oracle 10.2.0.4.
One of the 6 databases is downstream from another database (lets call it streamdb) on a Windows server. The Windows server is constantly streaming data to streamdb.
Now the problem:
The problem is that every time we start an RMAN backup for one of the other databases (called slowdb), the paging spikes (like from 0 to 50,000+) and the OS's response time degrades considerably. The backup takes between 10-15 minutes.
For the other databases the paging spikes as well during RMAN, but there is no server impact. To be fair, the database causing the degredation is 60GB in size and the other databases (that are supposedly not affecting the OS) are 30GB (one of them) and less than 3GB for the others. So RMAN runs less than a minute on them and may not have time to degrade the server.
To see if it was just RMAN or Oracle in general, I ran stats on the SLOWDB database. It ran for 1.5 hours and although paging was high, there was no impact on the OS. This makes us think it's something to do with IO to the backdg disk group.
Oracle Support has directed us to work with IBM support to review our IO configuration.
But we don't have IBM support and have only novice knowledge of IO configurations.
We are hoping that there's an expert on EE that can assist.