[Gllug] Hacker Attack, and a wild aside about version-controlled filesystems

[Daniel P. Berrange]

On Wed, Jan 11, 2006 at 10:54:44PM +0000, Nix wrote:
> [wild aside]
> 
> 
> I'm thinking a lot about revertability right now 'cos of my current
> spare-time obsession. I've just completed the design of a
> PostgreSQL-backed, version-controlled FUSE-based filesystem I'm calling
> Recant. Coding is underway as of three hours ago :)

Personally, I've been permanently put off the idea of versioning filesystems
having had to deal with the abortion that is IBM/Rational ClearCase and its
MVFS filesystem. One of many problems with MVFS was that it tried to mirror 
the entire of your existing VFS hierarchy & apply versioning to it, rather
than just providing a standalone versioned storage bucket you could mount
anywhere. With the mirroring approach it turned out to be very very hard to
passthrough correct semantics for all the wierd custom filesystem types like 
devpts, proc, sysfs, etc, no to mention the you now have interactions of two
layers of inode caching, locking, god knows what. The end result was using
MVFS tends to break various things, psuedo TTYs for example - /dev/pts now
has a filesystem type 'mvfs' instead of 'devpts' which confused glibc...

Still don't let IBM's horrific mistakes discourage you - even with using
FUSE & PostgreSQL I'm sure it'll be faster than MVFS ;-P

Regards,
Dan.
-- 
|=-            GPG key: http://www.berrange.com/~dan/gpgkey.txt       -=|
|=-       Perl modules: http://search.cpan.org/~danberr/              -=|
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|=-   berrange at redhat.com  -  Daniel Berrange  -  dan at berrange.com    -=|
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