[linux-lvm] Re: raid 1 on a single disk

["Måns Rullgård" <mru@inprovide.com>]

Greg Freemyer <greg.freemyer@gmail.com> writes:

>> 
>> P.S. I'd be really tempted to talk to the person asking you to do
>> this, and ask them what they hope to achieve...
>> 
> I can almost envision times it would be useful.  i.e. disk speed is
> unimportand, disk data rarely changes, but when it does it is very
> important, and traditional backups are not feasible for some unknown
> reason?
>
> By having the data written to 2 different places on the disk, the
> likelyhood of a failure making it  truly unrecoverable is extremely
> small.

Shall I tell you about the 80GB disk I had that suddenly dropped dead,
refusing all form of communication?

> ie. If you have disk media problems, likely only one location of the
> other will be affected.
>
> If you have a drive electronics failure, you can ship the drive off to
> have recovery performed.  (Over $1000 I know, but if the data is
> important.)

I'd rather pay the $100 for a mirror disk, which is also what I do in
my systems, after the lesson learned from the aforementioned failure.
I got four new disks, and configured them as RAID5.  Within a month,
one of them failed.

-- 
M�ns Rullg�rd
mru@inprovide.com