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Implementing Siebel eBusiness Applications on DB2 UDB for OS/390 and z/OS > Migrating Data Using Siebel EIM > Setting Up EIM for DB2 >

Optimizing DB2 Database Logging

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The number of parallel streams that the DB2 UDB for OS/390 and z/OS environment can support is often limited more by the DB2 logging throughput rate than anything else. The commit process waits for a successful write to the active log and, if there is contention on the logs, performance suffers. Possible solutions to ease bottlenecks caused by logging performance include:

Increase the number of output buffers for writing active log datasets. The size of the output buffer can be changed in DSNZPARM OUTBUFF.
Increase the active log size. If logs fill up faster than they can be archived, performance suffers.
Determine the optimal number of DB2 active logs based on peak EIM loads plus a cushion.
Place the active log data sets on separate dedicated volumes.
Place archive logs on a virtual tape system (VTS), or disk if VTS is not available.
Define all table spaces (base tables and interface tables) with compression, which reduces logging, and decreases I/O.
Consider data sharing when a single subsystem cannot handle the logging tasks.

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