Friends:

On a z/OS platform, we have five DB2 v7.1 subsystems, one of which is a production subsystem that needs a lot of love.

We believe that our production buffer pools are undersized and have been collecting statistics which indicate this situation.

The gatekeepers of z/OS memory, however, say that the DB2 bufferpools for ALL of the DB2 subsystems on this mainframe cannot exceed 2Gb.

Our understanding is that this 2Gb limit exists in each DB2 subsystem.

We need facts on this matter -- what is true?

If we're correct, we should be able to convince the gatekeepers to free up some memory for our use in buffer pool deployment.

If they're correct, it seems that we'd want to move some of those five subsystems, as the non-production subsystems would be perceived as consuming some of the available buffer pool memory resources.

Thanks in advance for your two cents' worth.

Barry Spiegel
EDS - Phoenix

You can use hiperspaces to extend bufferpool memory

Cheers
Sathyaram

Sathyaram:

Thanks for your reply.

We're aware of hiperpool space, but we appreciate the reminder that we can use this memory to extend buffer pools.

Can you confirm that buffer pool memory in one DB2 subsystem doesn't "borrow" that memory from a resource that impacts other DB2 subsystems on the same mainframe? That's what I was hoping to verify. My understanding of buffer pools is that the 2Gb limit (really 1.6Gb as an effective limit) is a limit within a DB2 subsystem. Can you confirm that?

Thanks, Barry

Barry Spiegel

barry.spiegel@eds.com