[Discuss] PCI RAID card for Linux?

[Alan W. Irwin]

On 2006-05-27 09:48-0700 Jim Roepcke wrote:

> On 26-May-06, at 11:00 PM, David Bronaugh wrote:
>
>>> Do you have any recommendations for PCI RAID cards (or have a better 
>>> idea?) that I can confidently use with Linux (and hopefully Dapper 
>>> Drake)?  Hopefully something that isn't super-expensive, I definitely 
>>> don't want to be spending hundreds but I honestly have no idea how much 
>>> these kinds of cards cost.
>> 
>> Don't bother with a RAID card, simply use both onboard IDE channels and 
>> use Linux software RAID. It'll work fine.
>
> Excellent!
>
> IIRC, if I put an ATA hard drive on the same channel as the ATA CD-ROM drive 
> the performance of the hard drive will suffer.  Is that true?  Should I be 
> worried about that or is that just a myth/bunk?
>

Jim's question sparked an additional one of my own.  Additional problems
with two disks are they generally cost more than one disk with the same net
storage capacity, require more power, generate more heat, etc. Linux
software raid works at the partition level rather than disk level so
RAIDing the partitions on a single device is certainly possible and naively
seems to deal with the two-disk problem Jim mentioned and the additional
two-disk problems I mentioned.  However, there is obviously no protection
against single-disk failure, and I suspect from further reading that RAIDing
partitions of a single disk actually give you no performance benefits either
so there is no point. Will someone with more than my superficial RAID
knowledge please confirm that "obvious" conclusion?

Alan
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Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state implementation
for stellar interiors (freeeos.sf.net); PLplot scientific plotting software
package (plplot.org); the Yorick front-end to PLplot (yplot.sf.net); the
Loads of Linux Links project (loll.sf.net); and the Linux Brochure Project
(lbproject.sf.net).
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Linux-powered Science
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