Re: [squid-users] Disk performance basics

    Shawn,

    We are a heavy user of ACLs. Besides, our traffic is authenticated (and
authorized). This is a eager CPU eater.

    Our Dell has 2 GB RAM, is a SMP machine (non-HT; two real processors and
disabled HT) and the load is quite balanced. One CPU gets a higher affinity
with Squid's internal things (since Squid isn't multi-threaded to take full
benefit of a SMP system) and the other deals with the interrupts, I/O,
authenticators, diskd, and other banal (but cpu-consuming) stuffs.

    We also rely on delay pools to disencourage some traffics (streaming,
webmails, etc). Altough not strictly prohibited, but the user willing to use
it, will have to face the line! :-)

    I have two machines doing the proxy service; a quad-xeon P III 700 with
3 GB RAM and 180 GB HDD (JBOD, 16 disks) and a Dell 3.2 SMP, 70 GB HDD.

    As weird as it may sound, my quad P III do the job better than the dual
P IV. Wait, don't blame the memory: Even when had 2 MB performed better than
the P IV.

    When we implemented a "load balancing" via dns (the name proxy has two
IPs, a very primmary LB) with these two machines, it brought us a very
pleasant result, with quicker response to the users. One of them (the Dell)
I've configured to force the cache of Windows Update and Google Earth...
It's just terrific!

    Well, that's it!

    Best regards,

    Rodrigo.

----- Original Message -----
From: "Shawn Wright" <swright@sls.bc.ca>
To: <squid-users@squid-cache.org>
Sent: Wednesday, March 29, 2006 9:15 PM
Subject: Re: [squid-users] Disk performance basics

> Thanks for the info. I've been using XFS for years, ever since SGI started
> patching RH for it, and have been very happy with it - fast, and solid as
> a rock. I'll
> have to look into epoll. I've got some time, as this won't happen for a
> few
> months.
>
> What are the current thoughts as to SMP with squid? I could buy more disks
> or
> RAM for the cost of the 2nd CPU. We went from a single CPU NT squid box to
> the current dual CPU linux squid box, so I can't really say whether the
> dual CPU
> makes much of a difference. We started out with async-io=24, which proved
> too
> much for the hardware, and have settled at 16 threads, which seems about
> right
> for the old box, and has proven to be very solid.
> How about RAM/cache space? Currently we have 768Mb RAM, 27Gb cache.
> I would probably go with around 2Gb RAM & 160Gb cache on the new box.
>
> We rely heavily on delay pools to keep bandwidth under control, giving our
> students 70kb/s max on their own PCs. Even at that, with the hours they
> are
> allowed to use it, we have some managing over 2Gb/day of downloads. With
> fast
> connectivity on the campus, they can really hammer the proxy during peak
> times, as our recent log-filling experience can attest to.
>
> On 29 Mar 2006 at 20:34, Rodrigo A B Freire wrote:
>
>> Shawn,
>>
>> Undo the RAID5 and leave them as single disks. Format the disks with
>> XFS. Use epoll.
>>
>> Be happy! ;-)
>>
>> ----- Original Message -----
>> From: "Shawn Wright" <swright@sls.bc.ca>
>> To: <squid-users@squid-cache.org>
>> Sent: Wednesday, March 29, 2006 7:29 PM
>> Subject: [squid-users] Disk performance basics
>>
>>
>> > Our aging squid proxy is due for replacement, and I am looking to
>> > maximize
>> > performance and stability on the new box. The current platform is this:
>> >
>> > Dual P3/733, Mandrake 9.2
>> > 768Mb RAM
>> > 4x 9Gb 10k rpm scsi drives on adaptec 3940, 1 for O/S, 3 for cache.
>> >
>> > The above has served well for a few years, handling a consistent load
>> > of
>> > ~500
>> > users, and about 350-450Gb/month of data. (with delay pools on most
>> > users).
>> > Long-term MRTG graphing of load shows the system is not CPU bound, with
>> > a
>> > steady avg CPU load of about 20%, avg http & dns times of 75ms, and
>> > typical
>> > peak requests/sec of ~60 each day.
>> >
>> > Our standard server is a Dell 2850 with 4 or more 15K drives and RAID5.
>> > Obviously RAID5 isn't needed for the cache, so I'm wondering what is
>> > the
>> > best
>> > disk option for cache performance in a machine like this, which offers
>> > up
>> > to 6
>> > drives in a scsi backplane.
>> >
>> > Any tips appreciated.
>> >
>> > Thanks.
>> > -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>> > Shawn Wright, I.T. Manager
>> > Shawnigan Lake School
>> > http://www.sls.bc.ca
>> > swright@sls.bc.ca
>> >
>> >
>> >
>>
>
>
> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
> Shawn Wright, I.T. Manager
> Shawnigan Lake School
> http://www.sls.bc.ca
> swright@sls.bc.ca
>
>
>
Received on Wed Mar 29 2006 - 17:38:05 MST