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 the swapoff, can you detach the vdisk? That's the only way with current technology to tell CP to free it up.
On 12/9/2015 12:05 PM, Mrohs, Ray (JMD) wrote:
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 after making sure that we have sufficient free memory available in that server. The reported swap use then effectively returns to zero. But it seems like nobody tells VM because the VDISK being retained in memory for that virtual machine, as reported by Velocity, is consistent with the maximum swap space that was used, something on the order of 190K pages, and it never decreases even though the Linux swap use stays at zero. Does VM ignore this until it hits a memory use threshold, or does Linux not clean up well after itself, or maybe we are missing something else? We are trying to avoid a "just reboot it" action. This is our typical swap disk entry in fstab: /dev/disk/by-path/ccw-0.0.0105 swap swap defaults 0 0 Ray Mrohs Lockheed Martin Corporation Service Delivery Staff Infrastructure Operations [email protected] 202 307-6896 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
