Re: [squid-users] H/W requirement for Squid to run in bigger scene like ISP

Hi,

One thing to keep in mind is that in my experience, it makes sense to
not only get fast disks, but put as much RAM in the box you can
afford. Now *don't* give this all the squid via the mem_cache config;
let the OS use the spare memory for caching disk reads. This will spee

Additionally, don't RAID your disks beyond RAID 1, and only do that if
you have to for reliability requirements. The more individual spindles
attached to separate cache_dirs, the better. Amos is right that I/O
trumps CPU here every time.

When we swapped out older squid boxes that couldn't take more than 2GB
of RAM, or more than one disk, and put in 64-bit boxen with 32GB and 3
cache-dirs (6 drives, paired into three RAID1 devices), we saw things
improve dramatically despite the fact that the CPUs were actually
slower. We went from topping out at 5K queries per minute to being
able to handle ~20K/minute without breaking a sweat. Pretty dramatic
IMHO.

Hope this helps,

-Chris

On Jul 14, 2008, at 10:04 AM, Amos Jeffries wrote:

> Anna Jonna Armannsdottir wrote:
>> On mán, 2008-07-14 at 13:01 +0200, Angelo Hongens wrote:
>>> All the servers I usually buy have either one or two quad core
>>> cpu's,
>>> so it's more the question: will 8 cores perform better than 4?
>>>
>>> If not, I would be wiser to buy a single Xeon X5460 or so, instead
>>> of
>>> 2 lower clocked cpu's, right?
>> In that case we are fine tuning the CPU power and if there are 8
>> cores in a Squid server, I would think that at least half of them
>> would
>> produce idle heat: An extra load for the cooling system. As You point
>> out, the CPU speed is probably important for the part of Squid that
>> does
>> not use threading or separate process. But the real bottlenecks are
>> in the I/O, both RAM and DISK. So if I was buying HW now, I would
>> mostly be looking at I/O speed and very little at
>> CPU speed. SCSI disks with large buffers are preferable, and if
>> SCSI is not a viable choice, use the fastest SATA disks you can
>> find - Western
>> Digital Raptor used to be the fastest SATA disk, dot't know what is
>> the
>> fastest SATA disk now.
>
> This whole issue comes up every few weeks.
>
> The last consensus reached was dual-core on a squid dedicated
> machine. One for squid, one for everything else. With a few GB of
> RAM and fast SATA drives. aufs for Linux. diskd for BSD variants.
> With many spindles preferred over large disk space (2x 100GB instead
> of 1x 200GB).
>
> The old rule-of-thumb memory usage mentioned earlier (10MB/GB +
> something for 64-buts) still holds true. The more available the
> larger the in-memory cache can be, and that is still where squid
> gets its best cache speeds on general web traffic.
>
> Exact tunings are budget dependent.
>
> Amos
> --
> Please use Squid 2.7.STABLE3 or 3.0.STABLE7
>
Received on Tue Jul 15 2008 - 03:23:11 MDT