Re: [squid-users] DiskD worthwhile for single-disk cache?

From: Adrian Chadd <adrian@dont-contact.us>
Date: Mon, 9 Apr 2001 00:42:11 -0600

On Sun, Apr 08, 2001, Steve Snyder wrote:
> Having read the Squid doc on DiskD, I am left with the impression that the
> primary (only?) benefit is to multi-disk configurations of Squid. True?

Kind of. diskd is designed to work around the problem of blocking IO
in a unix process. asyncufs gets around this by using threads to complete
disk IO. diskd uses external processes to complete disk IO.

I believe that asyncufs works just that little bit faster, but only
works on systems where threads can do async disk IO without blocking
the main process. Systems with user-threads (eg FreeBSD) can not use
this effectively. Diskd, being implemented as an external process,
gets around this.

> I'm wondering if enabling DiskD gets me anything on my single-disk cache.
> This is on a SMP Linux system, if that makes a difference.

You'll find that if your cache is slightly active you won't notice
a difference. diskd/aufs are only useful when the cache is under
high load.

Adrian
Received on Mon Apr 09 2001 - 00:42:11 MDT

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