[Gllug] XFS_repair cannot find master or secondary superblocks

[Steve Nelson]

On 3/3/06, Tethys <sta296 at astradyne.co.uk> wrote:
>
> "Martin A. Brooks" writes:
>
> >Not wishing to be cruelly pedantic but, no, it's not.  A copy on disk is
> >_not_ a backup.
>
> Whatever makes you come out with such rubbish? It may not always be a
> true backup, but there's no reason why it shouldn't be. I do all of my
> backups to disk.

It depends on context.  In a professional environment, backups are
something you utterly rely on.  They are what you use if your system
fails.  They are your get out of jail card.  For this reason, I don't
think its unfair to say that a copy of your data on another disk, even
part of a RAID set, is poor backup strategy.  I would go so far to say
that it *isn't* a backup strategy - as we've seen - its broken, its
unreliable, and it itself would need a true backup in order to be
reliable.

In this environment, the definition of a backup is a copy of data on
industrial grade tape, stored off-site, in disaster-proof conditions.

If one of my machine's root mirror explodes, and someone says "where's
the backup", my answer will be on such and such a tape, in such and
such location.  If the answer was "oh, its on that RAID 5 / XFS setup
over there", I wouldn't expect to be taken seriously.

For my personal use, yes, I have 'disk-based' 'backup' strategy - ie a
4 disk RAID 1 /data partition in a machine, to which various backup
images are copied on an automated basis.  This allows quick, cheap and
reliable restores of non-critical data.  I suspect this is as reliable
as cd or dvd, but I also burn disks from time to time.  Any genuinely
important data gets replicated to my work machine, and backed up
properly.

S.
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