RE: Linux filesystem speed comparison

> -----Original Message-----
> From: Joe Cooper [mailto:joe@swelltech.com]
> Sent: Tuesday, April 12, 2005 5:41 AM
> To: Steven Wilton
> Cc: 'Squid Developers'
> Subject: Re: Linux filesystem speed comparison
>
> The only test I know of that accurately predicts how a proxy will
> perform when given real load is Polygraph. And depending on the
> hardware configuration, either ext2/ext3 or reiserfs will easily
> outperform xfs. In my experience, ReiserFS is a better performer
> assuming CPU is not a bottleneck. But it is a much heavier
> user of CPU,
> and so some test results (like Duane's extensive benchmarks
> from a year
> or more ago) show ext2/3 performing measurably better than
> ReiserFS. A
> Polymix-4 test will fill the cache twice and then begin the
> test...so it
> takes into account the decline in performance that hits all
> filesystems.
>
> It depends on the balance of hardware, but I'd be extremely
> surprised if
> XFS performs better than either reiser or ext2/3 for Squid
> workloads on
> /any/ system. So I have to assume your methodology is
> slightly flawed.
> ;-)

That's what I thought, but there has been a bit of XFS work in recent
kernels, and after my initial observations I was wondering if this has
improved the performance with squid's filesystem load.

> While I have found that ext3 (when configured correctly) has improved
> performance for Squid quite a bit over ext2, it is still no match for
> ReiserFS on our hardware, which always has more than enough
> CPU for the
> disk bandwidth available. But, I can certainly imagine a hardware
> configuration that would lead to ext3 performing better than ReiserFS
> (especially since Duane has proven that it is possible by putting 6
> 10,000 RPM disks on a relatively wimpy CPU and testing the
> configuration
> extensively with polygraph).

The machines are a bit old (P3-500), but they've only got 3x 9Gb SCSI cache
disks, and they're not running anywhere near 100% load.

> I'm always interested in conflicting reports, however. If
> you've got a
> case that makes XFS faster for Squid against polygraph, I'd
> love to see
> the results and configuration.

I had a quick look at polygraph before, but I didn't get very far in testing
it. I would like to produce some polygraph figures for the proxies, so I
will see what I can do to make a test system. My only concern is that the
proxies may be able to process requests faster than the polygraph hardware
can serve them.

From memory there are a lot of options available for polygraph, and I was
not sure how to produce meaningful results. Any help would be appreciated.

Regards

Steven

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