RE: Cheapest way to acheive RAID5 ?

["Hawes,Timothy Edward \(GEG\)" <haweste@xxxxxxxxxxxxxxx>]

Thanks Lee,

I was thinking about common mode failure for drives as I was typing - a
good point to raise.
As you've probably already guessed, I'm not an expert on the subject ;-)
but if a disk fails in a non RAID array do you have to rebuild the array
from scratch, or can you only replace the data which was lost? If it's a
full rebuild I guess that's where RAID pays off - you're back up and
running much quicker and with less interruptions in service.

I suppose the moral is that if you want to keep it, make sure you back
it up :-)

Cheers,

Tim.

> -----Original Message-----
> From: LeeUKHA
>
> Yes, but...
>
> I would start slowly buying drives now from different suppliers...
> ...if you buy a job lot that all came from the same batch the
> likelihood is that they could all fail at the same time (all
> made at the same time from the same components and subjected
> to the same thumps and bumps?)...
> Look back though the archive and you'll see a lot of horror
> stories about multiple drive failure taking entire RAIDs out...
>
> Depending on your paranoia, you can run RAID5 with 'hot
> standbys', drives that are connected but unused and spun
> down, ready to jump in when things start to go wrong...
>
> It's also worth pointing out that DVDR's are only 15p each
> now, and are probably the most indestructible way to back up movies...
>
> Lee
>
> > Lee,
> >
> > Indestructible no, but it should be more resilient?
> Obviously with two
> > disks failing at the same time you're stuffed but you
> shouldn't lose
> > the lot from a single failure, should you?
> > I guess buying n+1 disks initially will then give you an spare
for
> > instant replacement on failure of the first drive and good spares
> > management would mean you'd then buy a new spare to replace the
one
> > you've just installed (and hope you don't get another failure
'til
> > it's delivered).
> >
> > Have I interpreted that right?
> >
> > Cheers,
> >
> > Tim.
> >
> > > -----Original Message-----
> > > From: LeeUKHA
> > >
> > > I think there's some confusion here, just because it's
> RAID5 doesn't
> > > mean it's indestructible...