My initial guess is that you need about 1 GB for your current workload.
Some things to check:
1. Do a QSYSOWN
qsysown
** Summary Information:
Total-Pages
Type Allocd In-Use %-Used
----------------------------------------
SPOL 1201680 348517 29.0
PAGE 1201680 172559 14.4
Look at the %-Used for PAGE. If it is near zero, where it should be if you
never paged, great. If it is not near zero, then you did/have been paging.
2. Find how much storage you are using. Do an IND USER for each guest:
ind user stlesa2
USERID=STLESA2 MACH=ESA STOR=700M VIRT=V XSTORE=NONE
IPLSYS=DEV 0120 DEVNUM=00073
PAGES: RES=00021448 WS=00021444 LOCKEDREAL=00000004 RESVD=00000000
NPREF=00011685 PREF=00000000 READS=00015515 WRITES=00051555
XSTORE=000646 READS=003233 WRITES=025769 MIGRATES=021694
CPU 00: CTIME=92:37 VTIME=721:27 TTIME=839:31 IO=335062
RDR=015839 PRT=790969 PCH=078332
Look at the RES figure. This is the number of pages that machine is using now.
Sum up all the pages for all the currently logged on machines, multiply by 4K
an that is the storage your guests are using.
3. Do a Q FRAMES:
q frames
All Frames:
Configured=163839 Real=163839 Usable=163839 Offline=0
Pageable=148743 NotInitialized=0 GlobalClearedAvail=32
LocalClearedAvail=32 LocalUnclearedAvail=31
The Configured minus Pageable....just say VM overhead.
Sum up 2 and 3 and that is the amount of storage you need at your current
paging rate (which should be near zero).
My guess is you have 6 GB left. 1 GB for your system. 1 GB taken for
microcode. 6 GB remaining.
Taking 2 GB for the zLinux LPAR is a good start. You will have a little more
than a GB for Linux stuff. On the Linux LPAR, make sure you have 4+ full
paging packs, as you are going to page here. Perhaps give .5 GB for expanded
storage, also, as you are going to page here. Don't forget to implement vdisk
support so you have vdisk packs for Linux swap areas.
Good time to also bring up vswitch/guest LAN.
Of course if you have a performance monitor, getting the right amount of
storage is a lot easier, but it is also doable manually.
How often can you reconfigure your production LPAR? If rare, push for a
performance monitor as it will save you Power On Resets as you keep
reconfiguring your production LPAR. If you can do it weekly/monthly, well,
take 2 GB, monitor for a while, take another 1 GB, monitor for a while, take
another GB, perhaps give back 512 MB. You know the drill.
Tom Duerbusch
THD Consulting
>>> Vince Getgood <vincent.getg...@xchanging.com> 9/14/2009 8:52 AM >>>
Hi all,
I'm not a VM expert, so forgive me if this seems a newbie quetion.
I have a z800 running z/VM, which has two production z/OS guests, and the
usual collection of CMS guests (TCPIP / OPERATOR etc).
We discovered recently that the z800 has an IFL (long story - don't ask!)
and would like to steal some of the 8GB currently allocated to VM, to run
up a VM / Linux LPAR for a POC.
The two z/OS guests are defined at 256MB & 512MB (Bill Gates, are you
watching??), and don't page.
In your most esteemed opinion, what could I steal from the VM LPAR without
hurting it's and the guests performance / making it page?
Personally, I think 2GB would be enough.
Comments and opinions welcome.
