I mentioned earlier some sort of preferred paging space for CP areas, kind of
like the DUMP area and SPOL.
But either way, it still depends on a Systems Programmer, which was the weak
link in this discussion.
Recall that a Systems Programmer caused the problem of authorizing an 8 TB
guest. And that System's Programmer will never do that again, IMHO.
So setting up preferred paging area, or paging pools, is just another thing
that most of us will never do, until we get shot in the foot.
I bet that there are more VM systems that are running without a DUMP area then
with. And they are the smaller shops that may be able to handle an outage
better than others.
The DIRMAINT exit to prevent this amount of storage from being authorized,
would have stopped it....that is, if the Systems Programmer did it.
Your VM performance monitor could have purged the machine and stopped it....if
the Systems Programmer did it.
I'm sure that there are a couple other ways of preventing the problem, like
IPL'ing the machine first and doing a Q V ALL to see what resources you really
did ask for, could have stopped the problem....if the Systems Programmer did it.
Perhaps we are just too dangerous to be around anymore <G>. Time to hide us
behind panels and such....
Tom Duerbusch
THD Consulting
>>> "John P. Baker" <jbaker...@comporium.net> 9/19/2009 11:21 AM >>>
All,
Since we have now beat the issue of storage management to death, I would
like to set forth some concrete ideas for consideration.
First, it has been pointed out that it may not currently be possible to
LOGON to MAINT or OPERATOR or to some other service machine in order to
diagnose the problem.
I recommend that the idea of splitting page space into multiple pools be
considered, where individual users can be assigned to different pools. For
the purposes of discussion, let us consider that following enhancement:
. In the SYSTEM CONFIG file
o DEFBACKSTGPOOL pool-id-8
o BACKSTGPOOL pool-id-8 volser-6
. In the CP directory
o OPTION BACKSTGPOOL pool-name-8
. Extend the CLASS B CP QUERY command
o QUERY BACKSTGPOOL user-id-8
o QUERY DEFBACKSTGPOOL
. Extend the CLASS B CP SET command
o SET BACKSTGPOOL user-id-8 {DEFAULT | pool-name-8}
. Extend the CLASS G CP QUERY command
o QUERY BACKSTGPOOL
Each paging volume will be allocated to a specific backing storage pool.
A LOGON will be rejected if the backing storage pool does not exist.
The SET BACKSTGPOOL command will be rejected if the backing storage pool
does not exist.
Second, provide a specification on whether a virtual machine requires full
backing storage for its defined memory size.
. In the SYSTEM CONFIG file
o DEFBACKSTG {SYSTEM | VMSIZE}
. In the CP directory
o OPTION BACKSTG {DEFAULT | SYSTEM | VMSIZE}
. Extend the CLASS B CP QUERY command
o QUERY BACKSTG user-id-8
o QUERY DEFBACKSTG
. Extend the CLASS B CP SET command
o SET BACKSTG user-id-8 { DEFAULT | SYSTEM | VMSIZE}
. Extend the CLASS G CP QUERY command
o QUERY BACKSTG
If BACKSTG is set or defaulted to SYSTEM, page allocation will continue to
operate as it does today.
If BACKSTG is set or defaulted to VMSIZE, there must be available within the
backing storage spool sufficient space to accommodate the entirety of the
specified VMSIZE, otherwise the LOGON, DEFINE STORAGE, or SET BACKSTG
command will be failed.
The SETBACKSTG command will force a virtual machine reset to occur.
These changes will address some of the issues raised. I am certain that
other changes would be required, and that other ideas should be considered.
Please post your ideas. Don't hesitate to point out any problems.
John P. Baker
