With Oracle, someone is listing to the PC side of the house. That is, inexpensive MIPS, inexpensive memory, expensive I/O. Hence you want SGA to be as big as possible.
On the IFL side, MIPS are still relatively expensive, memory is still relatively expensive, and assuming you are on FICON, I/Os are cheap. Since you are just testing, cut the SGA in half, make the Linux guest about 512 MB bigger than the SGA, make the swap disks, VDISKS and prioritize them. You shouldn't have VM paging. If you are planning on pounding I/O during the testing, don't forget I/O balancing on you DASD subsystem. Make sure heavy I/O is spread across raid arrays and controllers. The default tends to be accending CUA tend to be on the same Raid adapter, until you jump to the next one. Now, if you are really doing a full up Oracle test, that is, a full set of applications, driven by some sets of test scripts, you are going to need someone to configure your system for performance (of course you have a performance monitor for VM....). Your current Oracle platforms were not setup for performance in a day. Don't expect that on the mainframe, in a day. But most testing, isn't in this arena and you can grow and tune the system as you go. It will be interesting to hear the progress of your testing. Tom Duerbusch THD Consulting >>> Rob van der Heij <rvdh...@velocitysoftware.com> 6/25/2009 10:11 AM >>> On Thu, Jun 25, 2009 at 5:56 AM, Marcy > Your guest is bigger than your real storage. If you need to do that > overcommitting (and you may not - see Rich's question about SGA sizes), Overcommitting resources is good, because it is the only way to enforce sharing resources. But defining a single Linux guest larger than your total z/VM storage is just bragging. And that is bad ;-) As Rich says, you can't reduce the virtual machine size without also adjusting Oracle's expectations (SGA and PGA). Otherwise Linux would need to swap those areas and things go bad as well with two managers involved. Rob -- Rob van der Heij Velocity Software http://www.velocitysoftware.com/
