Re: [squid-users] Proxy server Spec..

On 15/08/2014 3:12 a.m., Stephan Viljoen wrote:
> Hi There,
>
> I’m putting together a new Proxy server for a medium sized ISP (4000 users
> plus) and would appreciate a few pointers from you good folks.
>
> I vaguely remember a debate a few years ago about SSD vs. conventional
> drives and was wondering which would be the best to use these days ?

It boils down to Squid having write-mostly behaviour with its caches.
That is something HDD cope with better.

There is some variance between SSD models write cycles. So YMMV, but
basically Squid burns through disks faster than manufacturer specs
indicate and noticably faster than with HDD.

We have also been improving Squid caching behaviour in ways that affect
these generalizations. Collapsed forwarding, Rock cache and related
in-transit object handling all reduce disk writes in the latest Squid.
So things are improving, but I am not sure how noticeably.

Whatever you do though, do not mirror or splice the cache drive(s) with
RAID. That just wears them out twice as fast, or kills two when one dies.

> Also ,
> apparently it’s better to use a higher Mhz CPU rather than more cores ? Is
> this still the case or does squid handle multiple cores better these days?

Yes to both. Yes Squid handles multi-core CPU better, but it is still
very intensive and better to have faster cycles than more cores. If you
can maximize both, even better.

>
> Also note , I’m thinking of rather boosting web performance rather than to
> save bandwidth. So I’m going to try and keep my cached objects as small as
> possible.

The two come as a package. The processing a proxy does always slows the
MISS traffic down. This is only compensated for by cache serving popular
objects as HIT faster than non-proxied traffic and reducing upstream
bandwidth (to allow for greater total throughput on MISS traffic).

>
> PowerEdge T620 NO CPU No RAM No HDD - 3yr Pro NBD
> 2 x Intel(R) Xeon(R) E5-2630 v2 2.60GHz 15M Cache 7.2GT/s QPI Turbo HT
> 128GB RAM
> 2 x 200GB Solid State Disk SAS 6Gbps 2.5"
>

NP: hyper threading does not count towards actual CPU core or cycles.

I recommend dedicating one CPU for the OS and the other to Squid. 1-2 GB
of cache_mem for memory caching, but no disk cache to begin with. See
how that flies, then expand it with disk cache if needed.

Amos
Received on Thu Aug 14 2014 - 16:39:17 MDT