Re: FileSystem Question
On Fri, Jun 29, 2007 at 06:45:03PM +0000, Manon Metten wrote:
>
> It's definitely no ordinary backup or RAID. It even works with a single hd.
> SFS takes care of all this. I don't have to backup anything. SFS just
> writes all subsequent copies of a file to different locations on the hd and
> moves the existing ones to .recycled (well, in fact it only updates the
> TOC). .recycled is just a hidden directory where all previous copies of a
> file are stored.
>
> This also means that in the rare case of a system crash when saving a
> file, I only lose that part of my work that was in memory only. The copy
> on disk remains untouched because only AFTER a new copy is written
> to disk (to a different location), the old copy will be moved to .recycled
> and the TOC will be updated. But in case of a crash during save, the
> new copy isn't finished and thus the old copy remains untouched and
> no TOC update is necessary. This whole process is completely hidden
> for the user. .recycled only comes to mind when I have to recover some
> data.
It sounds like the Log File System (LFS) that NetBSD is working on, or
the database-style of a mainframe where every 'file' is really a record
in a database where back copies are maintained until the space is
needed.
I haven't seen anything like this in Linux.
There was one application where I needed this and it implemented it with
a postgresql database with the files being 'huge' objects.
I've never used it but you can probably use a CVS repository for this
more conveniently.
Doug.
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