[aklug] Re: Reasonable average server load?

On Wed, 23 Jun 2010, adam bultman wrote:

> In my case, the ESX host decided to put the guest's RAM into swap, so
> the guest had no idea it's active memory was swapped out. I sent the
> results of just about everything on the guest (sar, vmstat, iostat, top,
> ps -efww) to engineers at a software vendor, and they could find no more
> than I could. I even made a cron job that ran any time the load went
> about 2 to send me an email with the results. Never found anything;
> sure did get some awesome eyestrain though.
>
> (And I suppose my NFS comment should have said, "saturated NFS mount or
> busy filesystem on the host". SAR on the guest won't tell you about
> NFS statistics if the NFS mount is on the host. You'll know that it is
> spending a lot of time waiting on I/O, but not particularly the "why". )
>
> Only logging into the ESX server and checking out a particular graph for
> the VM clued me in to the fact that ESX had decided to swap out the RAM
> of the only VM it was running (and, I might add, needed only half the
> RAM that the ESX server had). I have a munin plugin for that sucker
> now, so I'll know pretty quickly if it happens again.
>
> That was a real bear of a problem to find, but an easy one to fix.

Ah, that makes more sense, then. Goes to show, though, that if you're not
monitoring the host with SAR you really have no idea what's going on.

Doesn't vmware support pinning memory so the guests RAM can't get swapped
out?

         --Arthur Corliss
           Live Free or Die
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Received on Wed Jun 23 20:13:48 2010