Davis, Jeff writes:
> Your indicate command shows that you have 8 users in the E list. This
> happens when you don't have enough available real storage to fit a user's
> working set in to real storage. When a user is in the E list, the system
> appears to be unavailable or down to that user. He cannot run. You can do
> a couple of things. The best is to get more real storage. Unfortunately,
> that's not so easy. Second, you can set your SRM settings to over allocate
> real storage. This will prevent users from going into the E list, but will
> also drive up your paging rate. Make sure you have plenty of paging
> resource to do this.
If you post the result of
QUERY SRM
along with
QUERY STORE
QUERY XSTORE
QUERY ALLOC PAGE
then we can check whether some of your SRM settings are unnecessarily
preventing the Linux guests from being dispatched. For example, if
your DSPBUF setting was inherited from one intended for CMS guests
then it may include a "reserve" for Q1 and Q2 guests which Linux will
never be able to make use of.
As Jeff says, the next most likely reason is that storage is not being
overcommitted enough. In the absence of the timer-on-demand patch and/or
fancy footwork with mm configuration changes/patches, CP sees the entire
storage allocation of each Linux guest as one large clumped working set,
despite Linux being fairly happy (usually) to have some of it ripped
away. Because of this, in many Linux situations you can allow CP to
overcommit real storage rather heavily (while increasing paging space
to back it, of course) without the paging space actually being needed
most of the time. That's the STORBUF setting for SRM.
There's also the LDUBUF setting which causes guests to be kicked into the
eligible list if CP thinks that they are loading the paging subsystem
too much. That estimate is calculated based on how many "exposures"
the paging subsystem has: basically, how many volumes it can page to in
parallel, modulo some tweakable multipliers. The Q ALLOC PAGE I asked
for above will let you work out if that's likely to need tweaking when
you start increasing STORBUF (and assuming Linux guests turn out to need
to page significantly).
--Malcolm
--
Malcolm Beattie <[EMAIL PROTECTED]>
Linux Technical Consultant
IBM EMEA Enterprise Server Group...
...from home, speaking only for myself
