I would suggest that you reserve pages, rather than locking them. You can get the same effect for a lower real storage cost. There are bound to be some pages that are hit once, but never again. Let CP page them out. Start with CP SET RESERVED at, say 80% of what you were locking, and then adjust it up or down until paging gets to what you feel comfortable with. If you are paging now, you may even find you can get a lower paging rate than you currently have .
And, as everyone else has told you, you do need some expanded storage. Ot herwise there will probably come a day when everything runs much slower -- kind of like fall ing off a cliff. There is always a "knee of the curve" phenomenon in performance (sorry I cannot dr aw you a picture), but expanded storage can make that curve considerably less sharp. On Fri, 3 Feb 2006 13:43:18 +0100, Rob van der Heij <[EMAIL PROTECTED] ware.com> wrote: >On 2/3/06, Stefan Raabe <[EMAIL PROTECTED]> wrote: > >> Our VM will have 4GB, only one Linux Guest with 1 or max 2GB storage, 512MB >> swap vdisk for this linux guest. >> Remaining storage 512mb is for CP, some VM Users (TCP, administration users, >> ...) and MDC. > >And in that case it *is* a Bad Idea. When you lock pages with z/VM 4.4 >they reside under the bar. Together with other stuff that needs to be >under the bar as well, your system will not work if you lock more than >1.5G or so, thus creating even more contention. And since you >mentioned you're using Performance Toolkit: depending on what you do >it will actually also go for pages under the bar. > >Why don't you run Linux in LPAR when you are so certain that you want >to dedicate part of your real estate to that server. Most z/VM >installations find that allowing CP to manage the resources (with some >help) is more attractive than doing it yourself by hand. Proper >measurements can show you whether resources spent on VDISK or MDC are >worth it or not. > >> Is there any advantage if some of the storage is used as expanded stor age? > >Yes, in your configuration you should define expanded storage. It's >for providing a hierarchy in storage management as well as a >circumvention to reduce the impact of contention under the bar. >Especially when the total active memory of your Linux server is >getting close to 2G (and unless you do things, eventually the entire >Linux virtual machine main memory will appear active to VM). >25% has been suggested as a starting point, but measurements should >help you determine the right value. The right value depends a lot on >what Linux is doing. And make sure to disable MDC into expanded >storage as I suggested yesterday. > >Rob >-- >Rob van der Heij rvdheij @ gmail.com >Velocity Software, Inc >======================== ========================= ========== =============
