After switching back to the older kernel, I can confirm that the swap usage has returned to normal, even during the backup time 6am-8am. (See attached graph)
I'm wondering if this has anything to do with NUMA, which sometimes prefers to use swap rather than memory that is slightly slower than the currently used memory. I am using a single Phenom II 955 processor (quad core) on an ASUS M4N68T motherboard and SL6.4 upgraded from 6.3 Regards Bill Maidment Maidment Enterprises Pty Ltd N.B. Any email disclaimer in the original message has been carefully ignored as it has no meaning in law. -----Original message----- From: Bill Maidment <[email protected]> Sent: Friday 5th April 2013 14:16 To: Orion Poplawski <[email protected]>; [email protected] Subject: RE: IO performance regressions with kernel-2.6.32-358 I too have noticed this with my backup processes since using this kernel. I have also noticed that swap usage goes much higher at the time of doing the backup (using tar with gzip compression), even though there is plenty of RAM available. In fact, the RAM usage goes down while the swap goes up !!!! I've tried setting swappiness to 0 but this only has a small effect. I'm now going to switch back to kernel 2.6.32-279.22.1.el6.x86_64 Regards Bill Maidment Maidment Enterprises Pty Ltd N.B. Any email disclaimer in the original message has been carefully ignored as it has no meaning in law. -----Original message----- > From:Orion Poplawski <[email protected] <mailto:[email protected]> > > Sent: Friday 5th April 2013 3:26 > To: [email protected] <mailto:[email protected]> > Subject: IO performance regressions with kernel-2.6.32-358 > > Is anyone else seeing IO performance regressions with kernel-2.6.32-358? > We have a SL6.3 machine that serves a dual purpose of VM host and runs > our amanda backups to local disk. Since booting kernel-2.6.32-358 our > backups are taking significantly longer (and estimates are timing out). > Have not yet had the chance to boot back to an earlier kernel. Since > it also hosts some VMs (although they tend to be lightly loaded) it > might more related to that. > > - Orion > >
<<attachment: Screenshot.png>>
