Date: Sat, 6 Nov 2004 00:08:17 -0600 From: Dan Nelson <dnelson@allantgroup.com> To: steve@drifthost.com Cc: questions@freebsd.org Subject: Re: Big Problem, Load Avg Very High Message-ID: <20041106060816.GJ10428@dan.emsphone.com> In-Reply-To: <20041106054206.82A8143D86@mx1.FreeBSD.org> References: <20041106054206.82A8143D86@mx1.FreeBSD.org>
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In the last episode (Nov 06), Steven Adams said: > We host a couple or sites on this server (not very big sites). My > server load is always around 0.90 - 3.40. Sometimes it will jump up > to 10-15. > > At random it will jump up to 30-40 load and I wont even be able to > get to the server, typing commands on the remote ip based kvm is VERY > slow sometimes missing letters. As soon as im able to get top running > it shows > > ==================================== > > last pid: 52614; load averages: 6.82, 15.75, 15.18 up 1+03:07:12 16:32:22 > > 462 processes: 1 running, 460 sleeping, 1 zombie > CPU states: 0.0% user, 0.0% nice, 0.6% system, 0.6% interrupt, 98.7% idle > > Mem: 615M Active, 68M Inact, 288M Wired, 29M Cache, 112M Buf, 1844K Free > Swap: 1536M Total, 555M Used, 981M Free, 36% Inuse, 12K In 500MB of swap used? You might have a process that's allocating too much memory and causing the rest of the processes to swap to disk. Try keeping a top session running all the time so you can monitor swap usage and see if you notice any processes taking more memory than they should. > I did notice once when running systat -vmstat the amr0(scsi raid) jumps up > to 99% busy copying 2-3MB/s for a few moments then goes back down.. That could be either regular disk activity or swap thrashing. "vmstat 1" will tell you (watch the fre, pi and po columns). > After one of the times it went to 50load it got this on the console > screen. FYI: amrd0s1h is /home partition > > Swap_pager: indefinite wait buffer: device: amrd0s1h, blkno: 103776, size: 32768 > Swap_pager: indefinite wait buffer: device: amrd0s1h, blkno: 130801, size: 4096 Most likely you're thrashing. I've seen a couple other people mention this error with 5.2.1, but not lately, so chances are 5.3 has fixed this particular problem. > It seems that its copying a lot of information to the swap drive and > is running out of ram, which I don't know why it seems apache is > taking up all of the ram for some weird reason? Not weird at all. If you are using perl or php modules, they can really suck up ram if you get a lot of page hits at once. You might want to look at using fastcgi to separate perl/php from the apache process itself. -- Dan Nelson dnelson@allantgroup.com
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