Schuh, Richard wrote:
We have been on z/VM 5.2 for 2 weeks and have seen the 2G bottleneck disappear
as expected. We have seen an ability to run more users as our main benefit. We
used to run into the 2G wall with about 100 TPF guests. We have run as many as
132 without complaints since 5.2 was installed. We did uncover a latent demand
for cpu time and regularly drive the system over 85% cpu.
Now that we have a baseline with our old configuration, we are ready to try to
tune our storage allocations and would like some guesstimates of how it should
be allocated. The particulars are:
Machine: z990 model 305
Storage: 56GB currently allocate as 30GB main, 26GB Xstore.
Software: z/VM 5.2.0, Service level 0601+
Workload: 90% TPF testing, up to 132 concurrent TPF machines ranging in size from 690MB to 2GB. These machines are driven by CMS machines running scripts, so they are more like batch machines than interactive. TPF acts more like Linux than z/OS.
Do the two Titans of performance (or anyone else) have any ideas about how ought to allocate storage as our first try?
How is your Xstore being used? Is it dedicated to TPF guests, or is it
for some VM function, such as MDC? (My guess is, MDC might be trumped by
caching in TPF and your disk subsystems, but the key word here is "guess.")
How are your paging rates, for that matter?
I'm surprised by such a low ratio of Main:Xstore, but since I've never
had TPF guests, what do I know?
Nick
