[clug] Backups

[Andrew Janke]

On 8/6/07, Nemo <wombat at nemo.house.cx> wrote:
>
> Whilst my media data is nicely seperated already on seperate drives, it's still not much comfort that all my bits only exist exactly once. I've probably been exceedingly lucky over the years, and some recent random data corruption on my /home (via nfs) has spooked me. (was never more than a couple of dozen bytes per file, across a range of applications (inkscape svg's, galeon bookmarks, jpegs from gtkam and gifs from wget). Fault appears to have been a dodgy NIC (skge driver) - no problems since replacement :)

Aye, random data corruption is a scary thing.  It is fine enough when
it is your own data as then what you loose is only your own
fault/problem.  When it is someone else's data however you rapidly
find yourself in brown undie territory. A while ago while installing a
9TB XFS Areca based Raid running Ubuntu myself and a friend (vlad)
happened upon this evil little bug:

   https://bugs.launchpad.net/ubuntu/+source/linux-source-2.6.17/+bug/88705

Still unresolved from what I can see. We discovered this about a month
or so _after_ we had copied over 4-5TB of old data and had the thing
running for a month or so....  There was much frantic activity
searching for old backups and the likes.

Of course we had md5'd and rsynced a number of directories before this
to check the data from the old RAID when we first started using it but
obviously none of those directories had a file that was larger than
1GB in it.

And I thought that I used to test new RAID systems exhaustively, now I
trust NOTHING! :)


-- 
Andrew Janke   (a.janke at gmail.com || http://a.janke.googlepages.com/)
Canberra->Australia    +61 (402) 700 883