[Beowulf] RAID for home beowulf

[Mark Hahn]

> So, maybe the bold question to ask would be: what would be the best RAID
> config for 3 HDDS and a max 6 node HPC cluster? Should I just use RAID 1

do you mean for each node?

> for the system partitions on one disk,  and RAID 0 for the simulation
> data placed on the same partitions on other two disks: after
> post-processing, the data is gone anyway... and with a good backup
> strategy, I don't have to worry about RAID0 not recovering from a disk
> fail...

you're going to back up a raid0?
in any case, I think you should consider net-booting and using the node
disks as a 3x raid0.  if the local files are really transient, then 
your startup script can just reinitialize the local disks every boot.
(which would leave you with a working node even after a disk failure or two!)
that's assuming you need or can benefit from the capacity or bandwidth.

>> or better yet, don't bother booting of the local disk.  simply make your
>> head/admin/master server reliable and net-boot.  it's likley that nodes
>> won't be functional without the master server anyway, and net-booting
>> doesn't mean you can't use the local disk for swap/scratch/...
>
> Well, I want to configure the net boot for all diskless nodes and use
> the master node and it's RAID for a performance gains with writing CFD
> simulation data against network communication and to be able to scale
> more easily.

I'm not sure I parse that.  net booting is orthogonal to whether or not
you store data locally or over the net.  but yes, gigabit is somewhat 
slower than a single modern disk, so local IO will win.