Paul
As Nuno says there are many posts about this in the archive - Nuno, if you could consolidate them as you've offered it would be brilliant!!
The main thing you have to be aware of is *memory* - for some reason the installer chooses 16 MB by default and does not prompt for the amount during setup (no, I never get tired of saying it, and yes, you can now vote for my wish re this :))
Under *ix platforms you may have to do some changes to you configuration to enable Cach� sizing up a huge chunk of shared memory - again it's been posted before.
For the specific question you ask, I guess it depends on how fast would the databases grow. I don't think fragmentation will be much of an issue but certainly dynamic expansion of the CACHE.DATs can imply some overhead and if you can plan against that it's better. Note, however, that this overhead is not significant and unless the database is forced to grow by many MBs daily it won't be a big issue.
HTH,
Ram�n
-- ZCacheLib - Open Source Extensions for Cach� http://www.zcachelib.org
