[sclug] large disc capacity system

[Alex Butcher]

On Tue, 15 Feb 2005, Derek M Jones wrote:

> Talking of large capacity disc systems.  I have been
> looking into building my own system to hold
> 3-4T of data that is processed is various ways.  It is
> essentially a single user data cruncher system.

Check <http://www.finnie.org/terabyte/> for the gotchas from someone who's
already done this (1.2TB for US$1600).

> Does anybody have any recommendations?
> I plan to use RAID 5 to provide some degree of backup.
> My current choice of components is:
>
> motherboard (I had planned to buy a 3ware card, but
> the following offers raid 5 sata in hardware)

Are you quite sure? <http://www.nvidia.com/object/feature_raid.html> says it
just does RAID levels 0, 1 and 0+1. Of course, if you have >=3 drives
connected (not really very safe seeing as you only have two independent
controllers), then you can do RAID5 in software, which is probably what
Asus' page is implying.

Further, remember that nForce-based boards require you to use nVidia's
closed drivers. Sometimes this will prevent you from upgrading the kernel
when you would otherwise wish to. It will also effectively prevent you from
filing bug reports with the kernel developers.

Finally, I bet that just like the 'RAID controllers' that Promise, Silicon
Image and Highpoint sell for the same market segment, the RAID functionality
is actually provided by the driver, so you're doing software RAID whether
you like it or not. There's nothing inherently wrong with that (providing
you're aware of the tradeoffs) but I reckon you're safer using Linux's
built-in 'md' RAID implementation than any of these funky RAID-in-the-driver
approaches. Certainly I would expect the implementation to be better-tested
and recovery better-documented.

> http://usa.asus.com/products/mb/socket939/a8nsli-d/overview.htm
>
> case (it seems that high end cases are aimed at overclockers
> and lan party people, rather than business use)
> http://www.thermaltake.com/xaserCase/tsunami/bwa/bwa.htm

If you can still find them, the Codegen ATX-9001 cases are quite good for
this sort of thing: <http://www.dansdata.com/cgcase.htm>. I bought two for
55GBP each in late 2002, including 350W PSUs.

> power supply (never hurts to have plenty of umph for all the
> discs I might want to add in).
> http://www.thermaltake.com/purepower/w049atx12v/w0049atx12v.htm

Good call. I'll probably be replacing the PSU in my main machine shortly
after some power-related funnies. I'll probably also buy PSU-less and buy 
seperate PSUs in the future. Some recent reviews of PSUs:

http://www4.tomshardware.com/howto/20021021/powersupplies-01.html
http://www4.tomshardware.com/howto/20030609/index.html
http://www4.tomshardware.com/howto/20040122/index.html
http://www.trustedreviews.com/article.aspx?art=1014

> derek

Best Regards,
Alex.
-- 
Alex Butcher      Brainbench MVP for Internet Security: www.brainbench.com
Bristol, UK                      Need reliable and secure network systems?
PGP/GnuPG ID:0x271fd950                         <http://www.assursys.com/>