Hi ToddAndMargo!

 On 2014.07.27 at 22:25:08 -0700, ToddAndMargo wrote next:

> >Why would you *want* that? Seriously? When backups of files, rather
> >than filesystems, are much more easily mirrored onto a read-only,
> >accessible target to allow people to recover their deleted files
> >quickly and cheaply?
> >
> >Even if you need to back up to tape, AMANDA and half a dozen other
> >technologies do a much better job with "tar" or "rsync" based backups.
> >
> 
> Hi Nico,
> 
> 1) It is *insanely* fast
> 
> 2) it is command line
> 
> 3) I am the one that does the recovering, not the user.
>    (I leave the backup drives unmounted when not on use
>    on purpose!  I do not want the user anywhere near
>    those drives.)

"Dump was a stupid program in the first place. Leave it behind."
"Dump may work fine for you a thousand times. But it _will_ fail under
the right circumstances. And there is nothing you can do about it."

http://lwn.net/2001/0503/a/lt-dump.php3


Seriously, don't use dump. Backup software that highly depends on fs
implementation is a very bad idea in modern world. Accessing data at low
level from fs mounted in r/w (i.e. the data might be modified, so
special tricks are required to extract meaningful copy) is just asking
for trouble.

Note also that dump is
1) highly unportable (in Linux: ext2/3/4 only, *BSD dump isn't
   compatible with Linux version and so on)
2) not supported in other UNIX operating systems anymore because its
   design doesn't work with modern file system design. dump/restore
   don't exist in Solaris 11 at all (official recommendation:
   zfs dump/restore for whole backups, cpio/tar/rdiff-backup/areca/etc
   for more agile backups). For AIX IBM recommends tar and cpio for
   file-level backup as modern replacements
   (http://www.ibmsystemsmag.com/aix/administrator/backuprecovery/Backup-and-Restore-With-AIX)

If are 100% sure that you need fs-level backup instead of file-level
backup, then don't ask for things impossible by definition (restoring
fs-level backup to another fs).


Yes, dump/restore are fast but they are able to do it by duplicating
parts of kernel fs implementation in userspace, which is why there will
be irresistible problems with them.

-- 

Vladimir