At 08:50 28-04-01 -0500, you wrote:
>I've seen ads for the commercial and pricey backup packages from
>Syncsoft, Veritas and so on which claim no problems with live backups
>on *nix or NT. I suppose they have some way of write-locking files,
>copy to memory, then releasing the lock, but how could these utils
>work at the block rather than file level?
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
--
Jesper Holm Olsen, Graduate student & UNIX System Administrator at the
Dept. of Computer Science, University of Copenhagen
Guitarist in the c64-band PRESS PLAY ON TAPE: www.hybrisnemesis.com/ppot
Email: [EMAIL PROTECTED] ************ Homepage: www.diku.dk/students/dunkel
