[Gllug] XFS_repair cannot find master or secondary superblocks

Tethys sta296 at astradyne.co.uk
Sun Mar 5 10:37:17 UTC 2006


Nix writes:

>> A backup is an indexed archive that guarantees a point-in-time
>> recovery of data to a time resolution decided by local policy. A
>> backup is distributed, is stored off or near line, and is non-trivial
>> to corrupt or delete.  A backup is on non-fragile media - a hard disk
>> drive will almost certainly not survive dropping 1 meter onto
>> concrete, a DLT tape almost certainly will.  A backup let's you see
>> what changed, when (within the above set time resolution), and
>> preferably whom it was changed by.
>
>By these definitions, I have never had a backup, I have never worked
>anywhere which had a backup, and I don't know of anyone who's had one
>either.

Indeed (although I have worked in places that have such a scheme).
I'd say a much simpler (and more sane) definition of a backup would be
"any system that allows you to recover data in the event of hardware,
software, user or environment failure. The amount of data available,
and the time period over which it can be recovered is dictated by
local policy. By that definition, I'm not quite there at home (no
off site copy means I'm susceptible to environment failures like the
house burning down). But everywhere I've worked recently has met the
requirements.

Non-fragile media? Why do I care if a hard drive might be corrupted if
dropped? It's in an array screwed firmly into a rack. If the rack itself
falls over, then yes, your disks will be screwed. But in that event,
there are probably other factors that are going to be more of a problem
anyway.

Tet
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