Re: [squid-users] optimizing squid and FreeBSD

From: Michel Santos <michel@dont-contact.us>
Date: Tue, 20 Mar 2007 00:37:53 -0300 (BRT)

>
> You can add kern.maxfilesperproc=8192 in /etc/sysctl.conf to increase your
> squid file descriptors to 8192.
> You may also have to change your kern.maxfiles parameter to say about 8192
> or 16384.
>

all this sugestions are kind of high, hardly you get over 2000 open files
unless you have a heavy loaded server, this starts somewhere over 6-10mb/s
sustained http througput when you may need more open files

when you use coss you do not get even close to half of it

on FBSD you ever should query your system as with sysctl kern.openfiles to
see what is going on and then when *really* coming to the limit you might
like to raise it a little and otherwise not

> Well if your proxy serves less than 30 requests per second, then ufs
> storage is fine. However if your demands are above 30 requests per second,
> then either diskd and aufs will be good. However you may need to tweak
> your kernel to implement diskd for FreeBSD.
>

you say it so easy as if were that easy, firstable what your machine
supports and needs is relative to the machine's processing power. There is
no such 30 req/sec limit or switch-over-rule ...

but I agree, on FreeBSd you might consider diskd but the difference is
small and depends on the machine and the throughgoing http-traffic and if
your HD can really take the load (or better: answer the requests in time)

so my opinion hear is using ufs is good and stable and fits high load for
whom is not a specialist in system fine tuning, if you are knowing nasty
kernel stuff *and* have really nasty hardware and like to get the most out
of it then you should go diskd - but - better having a perfect UPS and a
server which never crashs, you may loss your cache content, anyway it's a
long way to get this 5-10% more (in comparism to ufs)

aufs? hands off

> Try using these in your kernel config file:
>
> options MSGMNB=8192 # max # of bytes in a queue
> options MSGMNI=40 # number of message queue identifiers
> options MSGSEG=512 # number of message segments per queue
> options MSGSSZ=64 # size of a message segment
> options MSGTQL=2048 # max messages in system
>
> options SHMSEG=16
> options SHMMNI=32
> options SHMMAX=2097152
> options SHMALL=4096

this values might be kind of unreasonable but probably does not influence
anything depending on your load, so you may not see if it is or not is
unless you monitor SHM and MSG on your system. So I believe when you can
live with SHMSEG=16 you do not need to set anything at all, it is lower
than FreeBSD's default

btw setting SHMMAX is old stuff, you should set SHMMAXPGS which adjust
automatically SHMMAX considering the other tweaked SHM values, if you do
it your way you may find undesired behaviour

anyway ipc.* are tunables so you do *not* need to compile them into your
kernel

if you want to tune diskd read first a lot of postgres sql tuning matter
which are the only lonly guys which seem ever having worked serious
(except me of course ;) ) with this IPC stuff on FreeBSD. What you find on
squid's website regarding FreeBSD makes diskd work on old versions but not
tuned.

michel

...

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Received on Mon Mar 19 2007 - 21:38:10 MDT

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