[ubuntu-uk] RAID 1 with three drives

[Samuel Toogood]

Alan Pope wrote: 
> 2009/3/2 Rob Beard <rob at esdelle.co.uk>:
> > The idea I had was if this is possible, I could attach one of the drives
> > externally via eSATA so it can be taken off site and in the event of a
> > server failure this off site backup could be plugged in and the server
> > could be back up and running in minutes rather than a good few hours of
> > re-installation (I was thinking of having two external drives so they
> > can be alternatively swapped every day).
> >
> 
> You'll need a script to re-add the disk into the array to start the
> sync, and yank it from the array before being unplugged, which is of
> course easily do-able with "mdadm".
> 
> Of course as soon as you add the disk back into the array you're going
> to cause a boatload of IO as the array resyncs from the internal disks
> back out to the external one, and that's going to happen _every_ time
> you plug the disk(s) in.
> 
> Cheers,
> Al.
> 
Are you thinking of this as the only backup? Recovery of accidentally 
deleted files might be a bit fiddly if so.

Sam