[Beowulf] Re: Beowulf Storage Node

[Matt Lawrence]

On Wed, 15 Apr 2009, John Hearns wrote:

> I politely disagree.
> We always built cluster head nodes with a mirrored disk pair for the
> systems disk, and a RAID 5 or 6 set with the rest of the disks in the
> chassis.
> If possible, you want a sensibly sized disk for your system disk -
> IMHO running terabyte-sized SATA drives as the OS drives on a system
> is inviting trouble. Get something small enough that you can readily
> back it up, and make sure it is mirrored.
> Then let the big data store look after itself - format it with XFS,
> run LVM on it, run RAID 6 on it.
> And if the worst happens and you lose your system disks, or indeed
> more likely you want to do a systems update,
> you UNLATCH A DRIVE AND PUT IT ON THE SHELF. Then you merrily
> update/patch/generally fool with the other drive (plus a replacement
> spare) and you have an instant fallback plan if things go pear-shaped.
> Sorry - I just don't buy having a RAID6 across all disks in one
> chassis. Unless you are booting over a SAN or something.

When management was breathing down my neck to maximize available storage, 
a RAID 6 across the six drives in the chassis seemed like the best option. 
There was certainly a lack of planning involved in this cluster, so many 
decisions were made in too much of a hurry.

-- Matt
It's not what I know that counts.
It's what I can remember in time to use.