In the past weeks one of my larger projects at work has been to set up an
efficient, responsive Squid proxy server, on a Linux (2.0.33) based system.
The server is up and running, and currently gets about 160000 hits (and
230000 misses) a day, nice and snappy.
I've learned a few things as I went along, some of which were rather obvious
in hindsight (things like SCSI disks are alot nicer than IDE - pay attention
Squid admins! :-). I've also run into some black magic I'd like to
understand..
After switching to Squid-NOVM because I was running out of memory (how do
people manage in only 128MB with >8GB of cache??) I ran into file descriptor
problems, in spite of having applied the 3000fd patch to the kernel. The
Squid FAQ suggested the following commands:
echo 32768 > /proc/sys/kernel/inode-max
echo 8192 > /proc/sys/kernel/file-max
This wasn't really explained well, I assume it is increasing system-wide
limits instead of per-process limits. I made this change earlier this
evening, so I don't know if it'll solve my problem or not..
So my questions are:
Will this make Squid stop complaining about a lack of file
descriptors? (It isn't anywhere close to using the 3000 fds the
patch allows, btw.)
What are the other files in /proc/sys/kernel ?
What other optimizations (tweaks) can be made via /proc?
Are the things in /proc/ documented anywhere? (are these FAQs?)
Another problem I wish I could solve can be seen in the following (fatal)
error message from my mailer daemon (sendmail 8.8.5 on a very busy machine):
[snip!]
----- Transcript of session follows -----
554 <username@my-domain.is>... openmailer(local): bogus mpvect -1073752948 +134318700
451 <username@my-domain.is>... Operating system error: Bad file number
[snip]
Could this be cured by the same tweaks? If not, does anyone know what
causes this? I searched some mailing list archives a while ago, but found
no solutions..
If I get useful replies I'll summarize to the list.. I'm sure there are
other people in my shoes.
P.S. Extra black magic for Squid admins: set your MTU to 576 (instead of
1500) to get better response times and solve networking problems with
some Netscape Enterprise servers (?) out there.
-- Thanks in advance, Bjarni R. Einarssonbre@margmidlun.is [ THIS SPACE INTENTIONALLY LEFT BLANK ] http://www.mmedia.is/~bre Juggler@IRC "Your revolution is a silly idea, yeah." - REM