Thanks Mohit. Shortly after you sent this last night I enabled system accounting. There's now a fair amount of data in the output but I'm not really sure where to find the disk wait times...
root@harold:~# sa
41065 44351.99re 428.71cp 11avio 823k
8678 33375.24re 418.23cp 34avio 496k httpd*
2469 51.19re 4.79cp 2avio 767k convert
1513 1180.51re 2.69cp 48avio 4929k php
2469 56.01re 2.59cp 2avio 1312k composite
590 3945.74re 0.09cp 5avio 6182k smtp
624 152.45re 0.09cp 0avio 196079k perl*
46 468.10re 0.08cp 691avio 574k cleanup
1170 10.05re 0.08cp 11avio 107305k rateup
47 388.52re 0.03cp 190avio 1054k pickup
743 240.80re 0.02cp 0avio 27976k trivial-rewrite
10443 1319.75re 0.00cp 0avio 26333351k sh
154 305.90re 0.00cp 24avio 44750k bounce
4454 101.21re 0.00cp 0avio 1753042k sendmail
4454 52.77re 0.00cp 7avio 2748826k postdrop
2 1.00re 0.00cp 0avio 3136k top
9 1278.02re 0.00cp 2avio 32944k ***other
389 13.73re 0.00cp 0avio 908587k ps
2 0.01re 0.00cp 6avio 981k sa
24 80.90re 0.00cp 0avio 60224k scache
9 35.12re 0.00cp 0avio 12700k anvil
78 0.28re 0.00cp 0avio 198900k atrun
623 1043.23re 0.00cp 0avio 959100k cron*
39 1.24re 0.00cp 2avio 112100k dd
27 52.78re 0.00cp 0avio 109600k error
65 114.24re 0.00cp 0avio 298000k flush
1165 41.51re 0.00cp 0avio 4475200k grep
40 0.14re 0.00cp 0avio 60000k jot
279 1.16re 0.00cp 3avio 971600k mv
7 0.31re 0.00cp 3avio 7200k newsyslog
13 1.68re 0.00cp 0avio 42500k proxymap
12 23.78re 0.00cp 0avio 78800k smtpd
40 0.16re 0.00cp 2avio 194800k unlink
388 14.47re 0.00cp 0avio 1219700k wc
Any help would be appreciated. Thanks.
-Stut
On 14 Jun 2008, at 00:43, Mohit Anchlia wrote:
try "sa"
On 6/13/08, Stut <stuttle@xxxxxxxxx> wrote: On 13 Jun 2008, at 23:38, Mohit Anchlia wrote:
look at "sar" output and see the wait times on the disk is more than the service time.
That command doesn't seem to exist on FreeBSD. Do you know if there's an equivalent command?
-Stut
On 6/13/08, Stut <stuttle@xxxxxxxxx> wrote:
On 13 Jun 2008, at 22:56, Dragon wrote:
Stut wrote:
On 13 Jun 2008, at 22:37, Dragon wrote:
Stut wrote:
Hi,
I have a problem with one of the web servers I manage. It runs
FreeBSD
6.2, Apache 2.2.8 and PHP 5.2.1. It runs a high-ish number of pre- fork
processes (usually around 240).
What basically happens is that during our peak hours in the evening
the site becomes very slow as does everything on the server. The top
output shows nearly all httpd processes in the state "devfs" and the
load is jumping up over 10 but the CPU is 70% idle. There's plenty of
free memory, over 4GB, and lots of available disk space.
While it's in this state all disk access is painfully slow. I've
checked all the drives and the RAID card status and everything
appears
to be fine. It also recovers itself after a few hours when the
traffic
dies down again.
I've spent a lot of today Googling but can't find any reference to
this particular combination of symptoms. Does anyone have any ideas?
---------------- End original message. ---------------------
It sounds to me like your system is waiting on disk resources (I am
assuming that is what the devfs state is), it is very likely trying
to use swap space.
Now much memory does this system have?
If it has insufficient memory to keep most things in RAM, it is
going to use a lot of swap and that will slow things down
considerably.
Oh how I wish it were that simple...
Mem: 1629M Active, 770M Inact, 392M Wired, 68K Cache, 214M Buf, 4791M
Free
Swap: 8192M Total, 8192M Free
No swap in use, plenty of free memory.
---------------- End original message. ---------------------
Well, I took my best shot on the info presented. I still think there is something in the disk I/O path that is acting as a bottleneck.
Sorry it isn't so easy, I have nothing else here. Wish I could help.
No worries, thanks for trying.
I agree that it's probably disk-related, but other than these symptoms I can't find anything wrong.
I'll see if the FreeBSD list can help.
-Stut
--
http://stut.net/
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