Phil, The generic approach I take is something along these lines: 1. For MDC to work, the I/Os have to be eligible for fast ccw translation. On Toolkit FCX179 SYSLOG display (or other monitor product), you'll see the rate of Fast CCW trans Done, Not Eligible, and aborted. See how your 800/second land there. 2. On FCX138 MDCACHE, check the fair share exceeded rate. As someone pointed out, MDC computes a fair share limit for inserts over a course of a minute. This will show how much the DDRs might be overrunning that. 3. On FCX112 USER display check the virtual DASD rate and the 'avoid' rate. The avoid rate includes MDC and VDisk I/Os that were satisfied without doing a physical I/O.
You mention you have 9GB for MDC. Another update I need to make to some of the doc is we do not recommend ever going above 8GB. Things don't work well at that point. In fact, in most cases you seldom need more than 2GB. There are various rules of thumb for this. Bill Bitner - VM Performance Evaluation - IBM Endicott - 607-429-3286
