[clue-tech] RAID no. of disks

[mike havlicek]

--- On Wed, 4/8/09, Angelo Bertolli <angelo.bertolli at gmail.com> wrote:

> From: Angelo Bertolli <angelo.bertolli at gmail.com>
> Subject: Re: [clue-tech] RAID no. of disks
> To: "CLUE technical discussion" <clue-tech at cluedenver.org>
> Date: Wednesday, April 8, 2009, 8:58 PM
> Yeah, I've read it all before. 
> With upwards of probably 2 Petabytes of 
> data at this point, we're not going to spend the extra
> money to have 
> completely redundant data.  Everything is a tradeoff.
>

If you had 12 drives and wanted RAID 5 tolerance (not using any spares)
what would be the comparison between say usable space and performance overhead in concatenating 2 packs of 6 disks, 3 packs of 4 disks, 4 packs of 3 disks, or one 12 pack to get one usable glob ?:) (Ooh and performance hit when you do start losing drives... or is it best not to glob it?

-Mike
> 
> Jack Parker wrote:
> > I try to keep my mouth shut.  Cruise over to
> comp.databases.informix and
> > google for "Raid 5 Art Kagel".
> >
> > j.
> >
> > Sane ego te vocavi. Forsitan capedictum tuum desit.
> >
> > -----Original Message-----
> > From: clue-tech-bounces at cluedenver.org
> > [mailto:clue-tech-bounces at cluedenver.org]On
> Behalf Of Angelo Bertolli
> > Sent: Wednesday, April 08, 2009 10:41 PM
> > To: CLUE tech
> > Subject: [clue-tech] RAID no. of disks
> >
> >
> > I know that things like RAID 5 need at least 3 disks,
> and can lose 1
> > disk.  The biggest RAID sets I set up are RAID 6
> with 12 disks, and
> > honestly that's pushing it a bit for fault
> tolerance.  But it does seem
> > to work.
> >
> > Does anyone on the list know if there is an upper
> limit to the number of
> > disks?  I am sure there must be, as the parity
> can't possibly be rebuilt
> > from just using one extra drive, if you have 1000 data
> drives, for
> > example.  I'm sure there has to be a tradeoff
> somewhere, like if I have
> > 1000 drives, I'm not getting a capacity of 999 drives,
> maybe more like
> > 900 drives.
> >
> > Angelo
> >
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