[Beowulf] Re: RAID for home beowulf

[Jörg Saßmannshausen]

Hi Tomislav 

I agree with what Skylar wrote. However, ask yourself what are you going to do 
with the cluster?
For example, I am doing quite a lot of molecular modelling, which requires 
plenty of RAM and also scratch space. 
So for the machines at the old University, I set up /boot and / as RAID1. Why? 
Failover is the answere. In case one disc dies, I have degraded, but working 
machine and the next possible time I can sort out the broken hdd. Actually, I 
had to do that a few times as somehow the IDE hdd seem to be a bit dogdy and 
broke quickly. Fortunately, within one day everything was back in working 
order (I swapped both discs in that occassion, so I had to mirror twice). 
There is a HowTo setup a failover boot as well.
( http://www200.pair.com/mecham/raid/raid1.html )

Also, if what you are doing needs plenty of scratch space, I would recommend a 
RAID0 and xfs. Best to do that as a hardware raid as it is faster than a 
software raid.

I hope that helps a bit.

All the best

Jörg


Am Samstag 03 Oktober 2009 schrieb beowulf-request at beowulf.org:
> Message: 2
> Date: Sat, 03 Oct 2009 19:41:28 +0200
> From: Tomislav Maric <tomislav.maric at gmx.com>
> Subject: [Beowulf] RAID for home beowulf
> To: beowulf at beowulf.org
> Message-ID: <4AC78CC8.5060500 at gmx.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Hi everyone,
>
> I've finally gathered all the hardware I need for my home beowulf. I'm
> thinking of setting up RAID 5 for the /home partition (that's where my
> simulation data will be and RAID 1 for the system / partitions without
> the /boot.
>
> 1) Does this sound reasonable?
> 2) I want to put the /home at the beginning of the disks go get faster
> write/seek speeds, if the partitions are the same, software RAID doesn't
> care where they are?
> 3) I'll leave the /boot partition on one of the 3 disks and it will NOT
> be included in the RAID array, is this ok?
> 4) I've read about setting up parallel swaping via priority given to
> swap partitions in fstab, but also how it would be ok to create RAID 1
> array of swap partitions for the HA of the cluster. What should I choose?
>
> I've gone through all the software raid how-tos, FAQs and similar, but
> they are not quite new (date at least 3 years) and there's no reference
> to clusters. Any pointers regarding this?
>
> Thank you in advance,
> Tomislav
>
> I'm starting with this:
>
> 3 x Asus P5Q-VM motherboards
> 2 x Intel Quad Core Q8200 2.33GHz (2 nodes with 4 cores)
> 1 x Intel Core 2 Duo E6300 2.6GHz (master node)
> 3 x Seagate Barracuda 320GB SATA 2 HDDs
>
> gigabyte Eth switch with 8 ports .... etc ...
>
> Best regards,
> Tomislav
-- 
*************************************************************
Jörg Saßmannshausen
Research Fellow
University of Strathclyde
Department of Pure and Applied Chemistry
295 Cathedral St.
Glasgow
G1 1XL

email: jorg.sassmannshausen at strath.ac.uk
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