Re: relkevance of subdirs under cache?

From: Henrik Nordstrom <>
Date: Wed, 27 Oct 1999 21:51:42 +0200 wrote:
> What exacltly is the logic behind specifiying the number of
> first and second level subdirs?

There is no logic. In my opinion you should only be able to specify the
L2 value. L1 should be derived from other basic parameters.

> e.g is 'cache_dir /squidcache 8000 16 256' better than 'cache_dir
> /squidcache 8000 32 256' even though the cache is the same size?

Neither of them is optimal.

* Your cache size is 8000MB.
* Agerage object size (store_avg_object_size) is 13KB
* This makes a on-disk object namespace of 8000 * 1024 / 13 file
* Squid stores L2 objects in each L2 directory before moving on to the
next L1 directory.

Or in short, it will use N = ceil(8000 * 1024 / 13 / 256 / 256) = 20 L1
directories. If you specify less then it will wrap around, so if you
specify 16 L1 directories then the first 3 will be used twice as much as
the other, and the 4:th directory will be user slightly more but not as
much as the first three.

What you need to tune is L2 to have each L2 directory in reasonable
size, and L1 to have it big enough to not wrap around.

Henrik Nordstrom
Squid hacker
Received on Wed Oct 27 1999 - 14:22:52 MDT

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