Re: Upgrading from squid v1.1.* to squid v1.2-beta18 ...

From: Henrik Nordstrom <>
Date: Mon, 06 Apr 1998 01:46:13 +0200

Henny Bekker wrote:

> Is it necessary to clear the cache, or is it possible to reuse
> the objectsin the cache by removing the squid log (index) file??

There is no upgrade path to save your cache when upgrading from 1.1.X to
1.2. Both the store log and cache file format has changed.

> [I've read something on removing all 'swap.state*' but these
> are not known yet on squid v1.1.*....]

This only applied to the upgrade from 1.2beta14 to 1.2beta15. I hope
duane removes this notice before releasing 1.2.

> - In squid v1.1.* the size of the cache was directly related
> to the size of the available RAM.. Squid v1.1.* uses approximately
> 64-Bytes of RAM for every object it holds in cache.. In squid v1.2
> this seems to be less..

1.1.X uses 52 + average URL length bytes per object (90-100 bytes)

1.2b18 uses 56 + 16 == 72 bytes / object

> What can be the size of the new cache with squid v1.2 with the
> same amount of RAM ??

Hopefully a bit more as 1.2 should not fragment the memory as much as
1.1.X does == it can make better use of the memory available. The amount
of memory needed for metadata is also a bit smaller.
To see the expected change in meta data size, take a cachemgr output for
your 1.1.X cache, note the number and amount of accounted store entries
and amout of memory for URL strings.

100 - 100 * ((store entries bytes + URL string bytes ) / number of store
entries ) / 72

should give how many percent you can change the cache size while having
the same amount of memory used for meta data.

> - Does someone know of a fast way to pre-load the cache with a
> number of most wanted/used objects??

1. Analyze your access logs to determine what is your "most wanted".
2. Run wget to fetch "the most wanted".

or ignore it and let the user actions fill the cache. The most wanted
objects is quite likely to enter the cache very quickly.

Henrik Nordström
Sparetime Squid Hacker
Received on Sun Apr 05 1998 - 16:50:59 MDT

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