DB2 10.5.6 Setting HEALTH_MON for CMOD 9.5

[JJeffrey]

We're currently in the midst of a Lifecycle migration of CMOD, DB2,  and TSM from RHEL5/AIX to RHEL7 and my DBA is questioning the use of HEALTH_MON = ON in DB2. It's currently set to ON in the live 9.0 system and wants to know, due to the overhead, of keeping it turned on for the CMOD 9.5, DB2 10.5.6, TSM 7.1 on the new server. My current DBA inherited CMOD Support from a previous DBA with few notes. What's best practice ON or OFF?

[Justin Derrick]

Since the IBM CMOD database isn't an Online-Transaction-Processing (OLTP) type of system, it doesn't really benefit from health monitoring & tuning.  The overhead is only a couple percent -- so if enabling it will cause performance issues, you have a bigger problem. 

If your DBAs don't have a database-monitoring infrastructure that reports on these types of statistics, it's probably not that useful.  I'd run it for a week or two after you get your new system into production, just to see if it has any recommendations for you, but then turn it off after that, and maybe revisit it yearly, or after you've applied a couple fixpacks.

-JD.