[geeks] Versioning FIlesystem

Dan Sikorski me at dansikorski.com
Sat May 24 11:36:05 CDT 2003


On Sat, 2003-05-24 at 10:50, Dave Kimmel wrote:
> The problem with storing only the diffs is that you need to keep all of
> the old data, or make the purge command flatten the data as it works
> towards the present version.  Also, it would limit you to the number of
> versions you could realistically have before reading the current version
> becomes unacceptably slow.  The advantage is, of course, the space
> savings.

I would think it would better to do reverse diffs, as in, keep the most
recent version as the whole file, and keep historical diffs.  It would
add a little overhead when writing out a file, but, then you could
easily get rid of diffs over a certain age without having to touch the
newer versions.  That way you could either have a command, or write a
script to delete all versions of all files older than a specific date. 
Which might be a good cron job. Have a cron job that either monthly or
weekly deletes all of the diffs that are older than 2 years or so. 
After all, if you need to go all too far back, there's always tape,
right?

	-Dan Sikorski



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