The link below is a VM Performance article with the ending "Bottom Lines" recommendations.
Has anyone done this and did it in fact improve performance? Bottom Lines |------------------------------------------------------------------------------| | | |For VM/ESA, if you have plenty of storage, little paging, a well tuned MDC, a | |consistent load, and a robust DASD paging configuration, then all real storage| |is most likely the best case. Otherwise, consider configuring some storage as | | expanded storage. A ballpark starting point is 25% of processor storage. You | | must configure anything above 2GB as expanded storage. | |------------------------------------------------------------------------------| |------------------------------------------------------------------------------| | | | For z/VM, you should still configure some storage as expanded. The 25% value | |may still be a good starting point. Most systems do not need more than 2GB of | | expanded storage regardless of the total storage available. Systems with no | | constraint below 2GB, can use less expanded storage. Constraint below 2GB | | often is indicated by significant paging to DASD and a large number of pages | | available above 2GB (as seen by QUERY FRAMES command or your favorite | | performance tool). In that case, you will want to add more expanded storage. | | You may also be able to free-up expanded storage by limiting the amount of | | expanded storage in use by minidisk cache (MDC) via the CP command SET MDC | | XSTORE or with a system configuration statement. | |------------------------------------------------------------------------------| www.vm.ibm.com/perf/tips/storconf.html TIA Jan Canavan
