XC is/was
required for SFS servers only if you want to make DIRC directories eligible for
dataspaces. It has nothing to do with XSTORE. And if I read the book correctly, XA or ESA should trump XC.
Use XC mode if you want to exploit data spaces
(SFS). For VMSERVS and VMSERVU, the IBM-supplied value is MACHINE XC. If you are using XA mode, you may want to
change MACHINE XC to MACHINE XA. In this situation, CP
allows an XC entry but automatically places you in XA
mode and issues a console warning message at every IPL. Changing MACHINE XC to MACHINE XA avoids the warning message.
Regards,
Richard Schuh
-----Original Message-----
From: The IBM z/VM Operating
System [mailto:[EMAIL PROTECTED]On
Behalf Of Steve Gentry
Sent: Tuesday, October 24, 2006
12:55 PM
To: [email protected]
Subject: Re: Extended storage
question.
Respectfully, Richard, I ran across
some doc somewhere that recommended that the MACHINE TYPE for VMSERx (U and S)
machines be set to XC so that
they can use XSTORE. Whether
VMSERx actually uses x storeage or VM itself handles these moves to and from x
storage is another matter.
If necessary, I will look up the
doc. regarding the XC recommendation. VMSERVS and VMSERVU come shipped
this way (MACHINE XC) from
IBM. VMSERVR is MACHINE XA ,
which, of course, makes sense.
Regards,
Steve
|
|
"Schuh,
Richard" <[EMAIL PROTECTED]>
Sent by: The IBM
z/VM Operating System <[email protected]>
10/24/2006 01:20 PM
Please respond to
The IBM z/VM Operating System
|
To: [email protected]
cc:
Subject: Re: Extended storage question.
|
VMSERVx machines are CMS. They are in the list of
those who cannot use it. They can benefit from having space allocated for MDC;
however, it is probably better to have MDC allocated from main storage rather
than XSTORE.
There are few operating systems that benefit from XSTORE, any
flavor of VM being principal among them. I do not know whether VSE can use
XSTORE, but you can add CMS, TPF and GCS to the list of non-users.
Regards,
Richard Schuh
-----Original Message-----
From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED]On Behalf Of Steve Gentry
Sent: Tuesday, October 24, 2006 12:05 PM
To: [email protected]
Subject: Re: Extended storage question.
You are correct, DASD paging is near 0.
"The only reason to attach XSTORE to a user
is if that user can actually do something with it."
So, are you saying that DB2, VMSERVS, VMSERVU, etc, need to have some XSTORE
attached to
them so that they will use it? On our system, these users have a USER
DIRECTORY with a MACHINE TYPE XC
Steve
|
|
Marty
Zimelis <[EMAIL PROTECTED]>
Sent by: The IBM z/VM Operating System <[email protected]>
10/24/2006 10:03 AM
Please respond to The IBM z/VM Operating System
|
To: [email protected]
cc:
Subject: Re: Extended
storage question.
|
Steve,
It sounds like you're a little confused about what Q XSTORE [MAP]
reports. In your current situation, you correctly point out that no
XSTORE is attached to any user. What this means is that it's all
available to CP for its two uses: primary page space and minidisk cache (MDC).
Judging from the third line of the result of Q XSTORE, you have MDC shut
off for your system. Thus, all of XSTORE is available as page space.
The demands of your system are such that only 21% of the available 4608M
are needed. (I suspect that your DASD paging rate is at or near 0.)
The only reason to attach XSTORE to a user is if that user can actually
do something with it. A CMS-based application cannot. Nor can z/OS
these days. My ignorance of VSE is complete enough that I don't know if
it can use XSTORE either.
The only additional information that Q XSTORE MAP gives you is to show
*which* pieces of XSTORE are attached to users, thus telling you what the
largest remaining contiguous chunk is. It does not (as you seemed to
assume) tell you whose pages are in the CP area used for page space. That
information is available in the Monitor data.
Marty
____________________
Martin Zimelis
Principal
maz/Consultancy
From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On Behalf Of Steve Gentry
Sent: Tuesday, October 24, 2006 11:02 AM
To: [email protected]
Subject: Extended storage question.
I trying to figure out what information I'm getting when I issue the Q XSTORE MAP command.
My current XSTORAGE is setup as follows:
q xstore
XSTORE= 4608M
XSTORE= 4608M userid= SYSTEM usage= 21% retained= 0M pending= 0M
XSTORE MDC min=0M, max=0M, usage=0%
XSTORE= 4608M userid= (none) max. attach= 4608M
I don't have any assigned to a specific user so I assume that the system (cp?)
is in control
of it and is thus allocating it as it sees fit.
As shown above, 21% is in use. But, who is using it?
I issue the Q XSTORE MAP
command and get the
following:
q xstore map
START SIZE STATUS
%-IN-USE %-UNUSABLE
0M 4608M
CP
21%
0%
I was hoping that it would tell me that userX was using so much, userY
was using so much, etc.
Or does a user show up in the q xstore map when the storage
has been attached to a
specific user? Say for instance I attach 1000M to a db2
machine/user. Will that userid then
show up in the list generated by the Q XSTORE MAP command? If
this is the case is there
a command that will tell me who
is using XSTORE and how much (either a percentage or a
total amount used).
And should I let the system allocate it or should I issue the attach statement?
I can see using the
attach statement if you absolutely want a user to have a specific amount of XSTORE
because of
a constrained environment. But what about non-constrained?
Thanks,
Steve G.
