Re: [squid-users] Configuring Squid v2.4 for GDSF and LFUDA replacement policies

From: Gino LV. Ledesma <>
Date: Wed, 13 Feb 2002 16:53:59 +0800

On Wed, Feb 13, 2002 at 02:14:25AM -0600, Joe Cooper wrote:
> I believe all you need to get the heap replacement policies in any
> recent version of Squid is:
> --enable-removal-policies="heap,lru"

Thanks for the clarification. I was wondering why I had two extra
directories upon checking the directories.

So then I guess its simply specifying heap GDFS or heap LFUDA in the
squid.conf file?

> Contrary to what you've read, the results of using the heap policies is
> rather minimal. In low storage environments, the difference may be
> worth noting, but in modern machines with hard disks way too big for web
> caching purposes already, any one of the policies will provide nearly
> ideal hit ratio. There is probably a small amount of benefit to using
> GDSF for memory replacement, because space is at such a premium and the
> more popular smaller objects are really best served from RAM. I've only
> done a few benchmarks of the impact of GDSF for memory replacement,
> and the impact is small enough to where I don't have any firm
> conclusions to draw about it--but it probably makes good sense in the
> real world.

I am quite interested in doing benchmarking. We have a rather heavily
used proxy that's serving at least 80-100 heavy/demanding users at any given time. Currently, I've been told that the proxies are configured using the default (stock) options for v2.2.

Aside from trying to use async-io/DISKD under GNU/Linux (which my friend
says was quite unstable/unreliable last time he used it), I've been
looking at lru, heap lru, etc as well. We're trying to do some
fine-tuning with squid to better improve the performance as it is.

> So, to put it in other terms: the additional replacement policies are a
> neat idea, and fun to poke at, but for most users they aren't going to
> really change the way Squid behaves either in hit ratio or in
> performance. (If you have a small hard disk, or a lot of memory to play
> with GDSF you're probably one of the users it will help.)

I'm not sure how much is a "lot", but one of the proxies we intend to
deploy has 512MB of RAM, whereas the others have 128MB. Hard Disk space
is a bit plentiful.

I guess I'll turn to other fine tuning articles once more. I've still to
read up on cache_mem and cache_dir tweaks.

Thanks again.

Gino LV. Ledesma
Ateneo Cervini-Eliazo Networks (ACENT)
email :
web :
phone : (63)(2) 426-6001 ext. 5925
Received on Wed Feb 13 2002 - 01:54:05 MST

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