Re: Status of VDISK after swap space usage

On Thu, 10 Dec 2015 14:05:26 -0800, Barton Robinson wrote: > If anybody in endicott is listening, ONE REQUEST. The current diagnose > used by the CMM function to release a page actually causes z/VM to read > the page in from the paging subsystem before releasing it. So release > 100,000 pages

Re: Status of VDISK after swap space usage

Has something changed in last 5 years? This has been in my standard SHARE presentations for the last 5 years, with CMM drop 20,000 pages, and there are 20,000 page reads. Drop another 20,000 pages, and there are 40,000 page reads (and 20,000 page writes becuase it was a constrained storage

Re: Status of VDISK after swap space usage

One possibility that occurred to me that would cause this "page in only to release" behavior is if Linux has the pages to be released on a linked list, and the linked list is maintained with pointers in the pages themselves, rather than an outside structure. If that's the case, then Linux has to

Re: Status of VDISK after swap space usage

It couldn't be pgmbk, this was a result of a LINUX CMM command, and it was the Linux storage assigned to the virtual machine that was targeted. On 12/11/2015 11:01 AM, Bill Holder wrote: Barton Robinson wrote: Drop another 20,000 pages, and there are 40,000 page reads (and 20,000 page writes

Re: Status of VDISK after swap space usage

Barton Robinson wrote: > Drop another 20,000 pages, and there > are 40,000 page reads (and 20,000 page writes becuase it was a > constrained storage experiment). Now that is rather interesting - that instance where the number of reads is exactly twice the number of pages being released maps

Re: Status of VDISK after swap space usage

On 12/10/2015 05:58 AM, Alan Altmark wrote: > On Wednesday, 12/09/2015 at 08:15 GMT, Barton Robinson > wrote: >> My request to get this fixed was rejected by ibm several years ago. The >> problem is that even though linux doesn't have anything on the vdisk, >> z/vm

Re: Status of VDISK after swap space usage

VERY COOL. So Linux has the technology, z/VM has the technology, now it just takes someone to use them. If anybody in endicott is listening, ONE REQUEST. The current diagnose used by the CMM function to release a page actually causes z/VM to read the page in from the paging subsystem

Re: Status of VDISK after swap space usage

Alan Altmark wrote: > E.g. possibly just re-formatting it could cause a formatted page to be released. We'd need some input from Bill Holder on that. Thanks, Alan. Yes, CP will recognize format write CCWs and release the corresponding vdisk backing storage. So I think that would mean SWAPOFF,

Re: Status of VDISK after swap space usage

On Behalf Of Mrohs, Ray (JMD) Sent: Thursday, December 10, 2015 6:18 AM To: LINUX-390@VM.MARIST.EDU Subject: Re: [LINUX-390] Status of VDISK after swap space usage It's a bit of a balancing act. Running zLinux lean and mean also opens up the possibility of extensive swapping under unusual

Re: Status of VDISK after swap space usage

>>> On 12/10/2015 at 07:07 AM, Bill Holder wrote: > Alan Altmark wrote: >> E.g. possibly just re-formatting it could cause a formatted page to be > released. We'd need some input from Bill Holder on that. > > Thanks, Alan. Yes, CP will recognize format write CCWs and

Re: Status of VDISK after swap space usage

: Wednesday, December 09, 2015 6:06 PM To: LINUX-390@VM.MARIST.EDU Subject: Re: Status of VDISK after swap space usage This is interesting. Having 2TB of page space in test/dev I'm sure we have some potential space savings if this could be done across all dev/test servers... However, you'd really

Re: Status of VDISK after swap space usage

to define its own VDISK. Aria -Original Message- From: Linux on 390 Port [mailto:LINUX-390@VM.MARIST.EDU] On Behalf Of Mrohs, Ray (JMD) Sent: Wednesday, December 09, 2015 3:05 PM To: LINUX-390@VM.MARIST.EDU Subject: Status of VDISK after swap space usage Hi, Our environment consists of SLES

Status of VDISK after swap space usage

Hi, Our environment consists of SLES 11.4 servers under VM 6.2. Sometimes we have misbehaving Linux applications that dip heavily into the SWAPGEN configured swap space. After things settle down, Linux never lets go of the space until we issue a swapoff -a, and swapon -a. Of course I do this

Re: Status of VDISK after swap space usage

My request to get this fixed was rejected by ibm several years ago. The problem is that even though linux doesn't have anything on the vdisk, z/vm still has to back it. I asked for a diagnose as we do with real storage - a way for Linux to tell z/vm the page no longer needs backing. So after

Re: Status of VDISK after swap space usage

@VM.MARIST.EDU] On Behalf Of Barton Robinson Sent: Wednesday, December 09, 2015 12:13 PM To: LINUX-390@VM.MARIST.EDU Subject: Re: [LINUX-390] Status of VDISK after swap space usage My request to get this fixed was rejected by ibm several years ago. The problem is that even though linux doesn't have

Re: Status of VDISK after swap space usage

On Wednesday, 12/09/2015 at 08:15 GMT, Barton Robinson wrote: > My request to get this fixed was rejected by ibm several years ago. The > problem is that even though linux doesn't have anything on the vdisk, > z/vm still has to back it. I asked for a diagnose as we