----- Original Message ----- From: "Andreas Dilger" <adilger@clusterfs.com> To: "Andreas Jung" <andreas@zope.com> Cc: <ext3-users@redhat.com> Sent: Friday, May 24, 2002 13:35 Subject: Re: High load on Squid server after change from reiserfs to ext3 > On May 24, 2002 13:01 -0400, Andreas Jung wrote: > > We are running Zope behind Squid 2.4Stable6 with squid in acceleration mode. > > The squid box (dual Pentium III 1 GHz, RH 7.2, Linux 2.4.9-21smp, 2GB Ram) > > has during busy hours a normal load of 0.2-0.3 . From time to time > > we see spikes over some hours where the load average of the machine > > is higher than 1.5 although there are no spikes in the CPU > > utilization. Also there is no increase in the number of incoming requests. > > > > The only change we made was the switch from reiserfs to ext3 for the cache > > partition since reiserfs corrupted its partition some time ago. > > One simple question - does the increase in the load value actually > affect squid performance? You say there is no increase in CPU > utilization. That may be good or it may be bad, depending if the "idle" > CPU is actually waiting on I/O to complete. > > What does the output of vmstat on both systems show? Please send two > traces, one during low load and one during high load. Our big brother diagrams show that the CPU utilization remains *low* all the time. I have been running vmstat on both machines when one of the machine had a spike. But both machines showed more ore less identical vmstat output: CPU was about 85% idle, no swapping, not much interrupts and context switches. In general, vmstat showed a perfect behaviour except that the load average went up on one box. Andreas
