Date: Wed, 27 Feb 2008 12:04:12 +0100 From: Kris Kennaway <kris@FreeBSD.org> To: Zbigniew Szalbot <zszalbot@gmail.com> Cc: freebsd-questions <freebsd-questions@freebsd.org> Subject: Re: sudden peak in load average Message-ID: <47C543AC.2090801@FreeBSD.org> In-Reply-To: <94136a2c0802270259i313331dcw45f8c26801f01636@mail.gmail.com> References: <94136a2c0802270259i313331dcw45f8c26801f01636@mail.gmail.com>
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Zbigniew Szalbot wrote: > Hello, > >>From the MRTG data I can see that suddenly on a currently not very > busy machine the load averege went over 15 or more. This happened > around 10 in the morning. Not many entries in httpd access log, smtp > server was not too much loaded (at that time it generally produces a > load average of about 1). > > But this time: > 2008-02-27 10:03:36 1JUICO-0002Bs-23 no immediate delivery: load average 15.88 > > Where can I look for more information about what happened. The server > was rebooted early in the morning so its swap consumption was almost > non-existent. Around 10 it suddenly consumed probably around 200MB of > swap, now it stands at 135MB which is pretty normal with this machine > (it only has 512 RAM). SWAP usage is normal with this machine but it > usually is a matter of 2-3 days before it gradually takes over 10-13% > of swap space. > > I tried by looking at: > http access log > auth.log > maillog > messages > > Nothing in there indicating an outburst of sudden activities. > > heh - I now think I may be wrong. The load average did not necessarily > produce so much swap consumption so fast. At 10:13 I run a cron job > optimising all mysql tables. So maybe in fact the swap was used by > mysql operations, although I am still interested to now what casued > load average to go above 15 at 10:03. > > 10:00AM up 3:14, 0 users, load averages: 0.40, 0.13, 0.05 > 10:01AM up 3:15, 0 users, load averages: 0.23, 0.14, 0.05 > 10:02AM up 3:16, 0 users, load averages: 0.08, 0.11, 0.05 > 10:03AM up 3:17, 0 users, load averages: 11.54, 3.09, 1.15 > 10:04AM up 3:18, 0 users, load averages: 13.26, 5.69, 2.28 > 10:05AM up 3:19, 0 users, load averages: 4.98, 4.69, 2.14 > 10:06AM up 3:20, 0 users, load averages: 1.79, 3.80, 1.99 > > > Thanks for any pointers. No way to know. You'll have to set up more detailed logging, e.g. a script that runs ps if load is over a certain limit. Kris
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