[Wylug-discuss] Help needed with 'failed' Linux software RAID 10

[John Hodrien]

On Mon, 28 Jun 2010, Paul Brook wrote:

> It seems to me that the simplest solution may be the best here. i.e. a
> single machine with a pile of disks, and one partition per disk. Maybe use
> LVM to carve things up to allow things to be rearranged later.
>
> Then have some sort of offline backup system. When a disk dies, replace it
> and restore that section of the archive from the backup.  Maybe have the
> system volume on a raid array so that a disk failure doesn't bring the whole
> machine down.
>
> I admit I'm not sure what state-of-the-art is for backups nowadays. I'd
> guess your options are optical media (blue-ray disks look comparable to hdd
> $/Gb), tape drives, cloud storage (too slow for large backups in a
> reasonable time), or an offline disk array (aka. a pile of esata/usb
> enclosures).

Overkill or not overkill... It's often quite hard to say.  I can see why you
think there's not any /need/ for redundancy, given the rarely changing data
making backups easy.

If you were buying all the kit now, the cost of redundancy isn't /that/ much.
4x2Tb + 4x2Tb for your offline mirror without any redundancy for 8Tb usable.
At the cheapest level, you probably just have a single machine and buy
USB/eSATA for the offline.  So assuming some of this data is changing, when
your single disk pops, you're going to lose some data.  Buy a single extra 2Tb
disk costs you 100 quid, and that disk failure now hasn't caused you any
problems.

That's assuming you trust your offline storage to work perfectly the one time
you need it to...

If you were looking at going to bluray for backups, then I'd really want to
only go to that as a last resort, so I'd definitely pay for the extra disk.

jh