RE: [squid-users] RAID is good (was: Re: [squid-users] Hardwaresetup ?)

From: Henrik Nordstrom <henrik@dont-contact.us>
Date: Fri, 28 Mar 2008 01:20:40 +0100

On Thu, 2008-03-27 at 12:21 +1100, Adam Carter wrote:

> Following on from my comment above, a single 20gig RAID0 cache_dir is
> probably not that much different to two 10gig cache_dirs on single
> disks. If using aufs then the RAID0 would only run as a single thread
> so that may adversely affect performance.

No, the minimum number of threads is 16, and increasing slightly with
the number of cache_dir.

> I guess that RAID0 would offer a worse seek time from squid's
> perspectiv as each request from squid is serialised, but data transfer
> rate will be higher for a particular object.

Negliable on both. RAID0 transfer rates only becomes visible on very
large batch requests, which is very rarely seen with Squid..

> I imagine squid is more sensitive to seek than throughput. I'm just
> speculating on all this...

Correct. Squid eats a lot of seek time, and fairly little bandwidth.

> Do you know what your "600 - 700 Req/Sec Polygraph polymix-4
> benchmark" is in Mbps?

Comparing Mbps with a simulation isn't that relevant. Req/Sec is a much
more reliable measure when comparing with real life.

Regards
Henrik
Received on Thu Mar 27 2008 - 18:21:45 MDT

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