[clug] Story: Fijian Resort complex loses a single disk: business process stops for 1-2 days

Brendan Jurd direvus at gmail.com
Fri Jul 25 03:23:52 MDT 2014

On 25 July 2014 10:53, steve jenkin <sjenkin at canb.auug.org.au> wrote:
> Enough people on this list run servers at home, work or at a hosting site for it to be relevant.
> The question posed but never answered at the meeting was:
>   “how do you create a backup system, at least for ‘2nd copy of precious data’, where you _know_ if it fails”.

My approach at home is deliberately low-tech.  I don't use RAID at
all, I just have two HDD in there: an operating drive and a backup
drive.  The important data gets copied to the backup drive by a cron
script.  For the particularly critical stuff I keep multiple

My theory is, if the operating drive fails, I am sure to notice
because my server will stop serving!  Then I just rebuild the server
onto a fresh primary drive, and copy the data back over from the
backup drive, then replace the backup drive (because if the primary
has failed, the secondary may not be far behind!)

It is quite unlikely that the secondary would fail first, since it has
so few writes going on compared to the primary.

Is it a perfect solution?  No.  If the data all somehow gets deleted
on the primary drive, without a drive failure, the backups will
eventually end being empty too.  But a) I consider that an obscure
enough risk that I am not freaking out about it, and b) a RAID
solution would have the same risk.


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