My instance is currently db2 8.2 fixpack9 and running on 32 bit. We plan to upgrade the instance to 64 bit soon. Is there a rule of thumb for how much to increase buffer pools after the upgrade ? Are there IBM documentations with suggestions ?

Thanks

Just make sure that you don't exceed the amount of physical memory on the machine when taking into consideration OS usuage, other application usuage, and all DB2 usuage of memory. DB2 does not like virtual memory (swapping).

Obviously, there is no need to create bufferpools that are larger than the total amount of space used in the tables and indexes.