I have MDC turned off on all linux client dasd volumes except the boot volume. The data volumes/file systems are large > 400GBs with random i/o over the whole file system.
-----Original Message----- From: Linux on 390 Port [mailto:LINUX-390@VM.MARIST.EDU] On Behalf Of Duerbusch, Tom Sent: Friday, December 18, 2015 3:08 PM To: LINUX-390@VM.MARIST.EDU Subject: Re: New Subscriber's first question. Hi Bruce A conversion piece that is frequently forgotten during VM upgrades is what is your MDC (minidisk cache) setting? Q MDC The default (perhaps use to be) all storage was available. Most of us set it to a smaller amount. Once it has been set, it is set forever (unless a performance monitor tells you to use a different about). And hence, easily forgotten. Those of us that run second level VM systems usually hit a "rude awaking" when MDC settings are allowed to run "free and wild" <G>. Tom Duerbusch THD Consulting On Fri, Dec 18, 2015 at 1:31 PM, Davis, Jim [PRI-1PP] < jim.da...@primerica.com> wrote: > Hi Bruce > > I had to backout the 630 upgrade while they finished upgrading their > apps to sles 11.4 which is running with very little paging if any at > all under > 540 with 4gb xstore and cmma=on in kernel parms. > > This Sunday I will try VM 630 again but without xstore and with 16GB > of central storage. > > Someone else replied that cmma has been removed from sles 11 but I > think I am using really using what is called cmm2. > > When we first started with sles 9 and vm530 the recommendations from > IBM were to let the linux swap to vdisk and only increase the vm size > when swapping became excessive. My linux clients have 2GB or less of > storage and at least 3GB of swap to vdisk defined. > The early write may be my problem as 630 would be writing all of the > vdisk pages to aux storage before cmma would tell VM to throw away the page. > > > -----Original Message----- > From: Linux on 390 Port [mailto:LINUX-390@VM.MARIST.EDU] On Behalf Of > Bruce Hayden > Sent: Friday, December 18, 2015 1:56 PM > To: LINUX-390@VM.MARIST.EDU > Subject: Re: New Subscriber's first question. > > Hi Jim, welcome to the mailing list. > > z/VM 6.3 had many changes to memory management, and it will use more > paging space. For one, it will write pages out "early", meaning > before it has to actually free up a page. As part of that, XSTORE is > no longer recommended and I'd suggest the next time you IPL, change > the LPAR configuration to 16 GB of storage with no expanded storage. > > Without knowing more details on your VM and Linux configuration, it is > hard to say why it is using so much more page space. Did the size of > the guests increase when you upgraded them to SLES 11? The CMMA > support in z/VM did not change between 5.4 and 6.3 but it may have > changed in Linux from SLES > 10 to SLES 11. > > On Fri, Dec 18, 2015 at 1:12 PM, Davis, Jim [PRI-1PP] < > jim.da...@primerica.com> wrote: > > > I am a systems programmer at Primerica Life Insurance. > > We have been running SLES linux under VM for nine years. > > We only have four production VMs on one lpar using a single IFL. > > > > We will be installing a Z13 in Jan 2016 which has required me to > > upgrade all SLES 10.3 VMs to SLES 11.4 and VM from 540 to 630. > > > > The VM lpar has 12GB of storage plus 4GB of xstore. > > Under 540 I did not experience any paging to external VM page datasets. > > CMMA=ON > > > > When I bring up VM 630, I see massive movement of pages to xstore > > and then page outs to aux storage, filling up aux storage. > > I have increase aux storage to 3x but it keeps growing. > > > > It acts like CMMA is not functioning under VM 630. > > > > Any assistance would be greatly appreciated. > > > > Jim Davis > > > > > > > > > > -------------------------------------------------------------------- > > -- For LINUX-390 subscribe / signoff / archive access instructions, > > send email to lists...@vm.marist.edu with the message: INFO > > LINUX-390 or visit > > http://www.marist.edu/htbin/wlvindex?LINUX-390 > > -------------------------------------------------------------------- > > -- For more information on Linux on System z, visit > > http://wiki.linuxvm.org/ > > > > > > -- > Bruce Hayden > z/VM and Linux on z Systems ATS > IBM, Endicott, NY > > ---------------------------------------------------------------------- > For LINUX-390 subscribe / signoff / archive access instructions, send > email to lists...@vm.marist.edu with the message: INFO LINUX-390 or > visit > http://www.marist.edu/htbin/wlvindex?LINUX-390 > ---------------------------------------------------------------------- > For more information on Linux on System z, visit > http://wiki.linuxvm.org/ > -- ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
