[Beowulf] RAID for home beowulf

[Skylar Thompson]

Tomislav Maric 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.
>   

Cool. If you have zippy processors the overhead of calculating parity
probably isn't going to be too high, so RAID 5 and RAID 0 will be
comparable. Sequential reads and writes are ideal for RAID 5.

> Sorry for the totally newbish questions.
>
> I'm using Ubuntu, and after I install it, I'll try to configure the RAID
> manually. How do I make sure that the boot loader is on all disks? I
> mean, isn't RAID going to make the OS look at the /boot partition that's
> spread over 3 HDDs as a single mount point?
>
>   

You'd mount /boot using the /dev/md? device, but point your boot loader
at one of the underlying /dev/sd? or /dev/hd? devices. This means
updates get mirrored, but the boot loader itself only looks at one of
the mirrors.

-- 
-- Skylar Thompson (skylar at cs.earlham.edu)
-- http://www.cs.earlham.edu/~skylar/


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