[squid-users] couple of squid questions

[Alex Sharaz]

hi all,
couple of questions re squid config
My squid hardware is based round systems with a 1.8Zenon cpu 4Gbytes of ram 
and 4 36Gbyte disks for cache storage running RH 8.0 with the 2.4.18-24smp 
version of the kernel. Each disk has 1 partition set up cachedir ufs 90% 
of disk space 256 256

what sort of cache_mem setting should I be looking for in the above config.

did have aufs set up for a while but seemed to have a number of error 
messages indicating that particular directories on a cache disk could not 
be found e.g. cache1/0a/ob  ... didn;t seem to have made any difference but 
I would have excpected a squid -z to have created all the directoroes it 
required.

Should I be aufs?

and lastly
given that the Zenon processors can support hyper-threading, is there any 
magical squid config settings that'll make use of this? Using 'top' it 
looks as if it isn't at the moment.

TIA
alex

Re: [squid-users] couple of squid questions

[Henrik Nordstrom]

On Tuesday 25 February 2003 09.40, Alex Sharaz wrote:
 hi all,
 couple of questions re squid config

 My squid hardware is based round systems with a 1.8Zenon cpu
 4Gbytes of ram and 4 36Gbyte disks for cache storage running RH 8.0
 with the 2.4.18-24smp version of the kernel.

If possible with your motherboard you may want to consider using a 
non-SMP kernel for increased system performance, but you probably 
need to compile your own to support large quantities of memory.

There is a quite high performance penalty paid when enabling SMP in 
the kernel, and the benefits of SMP is mainly seen if the 
application(s) can really use more than one CPU. Squid is not at all 
good at using more than one CPU.


 Each disk has 1
 partition set up cachedir ufs 90% of disk space 256 256

You need more than 256 L1 directories for such large cache 
directories..

   L1 = at least cache_size(in kb) / L2 / L2 / 8 * 2

 what sort of cache_mem setting should I be looking for in the above
 config.

Not too large. Even if your server have 4GB individual applications is 
still limited by the 32bit pointer architecture of the Xeon processor 
to about 1.5GB each in the best conditions..

See the Squid FAQ on memory usage for how to calculate how much memory 
Squid will use for your cache directories. Then use no more than 50% 
of what is left of the maximum process size for cache_mem.

 Should I be aufs?

Quite likely. If you get unexpected errors please report these errors, 
exacly as they are given.

 given that the Zenon processors can support hyper-threading, is
 there any magical squid config settings that'll make use of this?

No. Squid is essentially a single threaded application.

Regards
Henrik