Re: Linus Torvald's opinion on Dump.

[Mitch Collinsworth]

> Veritas file-system (VxFS) can make what they call a 'snapshot' of a file
> system. The idea is to take a "snapshot" of a filesystem and mount it as
> readonly on another device. Whenever a block on the original filesystem is
> altered the old one is copied to the snapshot and thus keeping this in the
> state it was in when mounted. This is for example used to backup using
> vxdump. Unfortunatly this is not yet available on Linux as far as I know -
> only Solaris and HPUX :(
> 
> A quick search on google revails that someone is working on this feature
> for Linux as well: http://lwn.net/2001/0308/a/snapfs.php3

This is a reasonably accurate description of how the backup system for
the AFS filesystem works.  And AFS is available for Linux, both as a
commercial product from IBM/Transarc, and as an open source project
called OpenAFS.

-Mitch