[Beowulf] RAID for home beowulf

[Lux, Jim (337C)]

On 10/3/09 1:48 PM, "Tomislav Maric" <tomislav.maric at gmx.com> wrote:

> First of all: thank you very much for the advice, Skylar. :)
> 
> So, all I need to do is to create the same partitions on three disks and
> set up a RAID 5 on /home since I'll be doing CFD simulations (long
> sequential writes) and use RAID 1 for other (system) partitions, to
> account for recovery of the system in case of disk failure because log
> writes are sequential and small in volume. I was reading about RAID 0,
> but I'm not sure how safe is to use it for storing computed data and how
> much speed would I get compared to RAID 5.
> 
> Sorry for the totally newbish questions.
> 

So why are you using RAID at all on a home cluster, other than to gain
experience with using/configuring/managing RAID?  I would think that a
decent batch backup scheme might actually be more cost effective.  That is,
if you stop your job every hour and mirror it, at most you lose an hour of
computing time, which is presumably cheap compared to extra disk drives.
For that matter, if you're doing software raid, the reduced performance from
doing the raid might be even a bigger effect than the potential loss of an
hour or two.