I am planning a DB2 software upgrade to our existing database servers. The sysadmin is also upgrading the OS and will require me to rebuild all servers. This gives me a rare opportunity to fine-tune our DB2 Production environment. Primarily I am thinking of consolidating our DB servers from 3 servers down to 1 server and run multiple instances.

I can't think of a valid reason why we wouldn't want to consolidate to just one db server. At the server level the only risk I can think of would be rebooting the server would bring down all DB servers. At the dbm level I would hard-code the INSTANCE_MEMORY for some of the troublemaker db's and let STMM handle the rest. I don't think we would ever run into any limits with DB2 software in terms of num#db num#instances, etc. Also we don't plan on running different OS or OS levels. I can upgrade DB2 and not upgrade an given instance. Is there something else I should be taking into account? - kernal/thread limits on the one server, i/o wait increases on disk?

Our evironment:
All DB's are using SAN storage for data/index/logs,etc., but Db2 is installed on the server's local disk.

Our total DATABASESIZE = 1.TB, no DPF. A couple db's run SQL replication and 6 are federated.

We currently have 11 databases spread over 3 db server LPARs. 3 db's are OLTP, 1 DATAMART, 2 mixed DATAMART and OLTP, and the rest are just one-offs (cognos,bug tracking,etc).

Thanks in advance,