LinuxSA Mailing list archives

  From: Alan Kennington <akenning@topology.org>
  To  : LinuxSA <linuxsa@linuxsa.org.au>
  Date: Mon, 4 Jun 2001 06:23:41 +0930

software RAID versus hardware RAID

Can anyone tell me the pros and cons of
hardware and software RAID?

It seems that if I have two 20 GByte disks,
I can pay $260 for a RAID card (and give up
my last remaining PCI slot) to get hardware RAID.
But with software RAID, I find this document:
http://www.linuxdoc.org/HOWTO/Boot+Root+Raid+LILO.html
which makes it clear that there is some complexity in
setting it all up.
Then again, it looks like I'll have some complexity
with setting up the hardware RAID too:
http://www.ram.org/computing/linux/dpt_raid.html

My objectives are:

-	The machine should keep running when one
	of the 2 disks fails.
-	An application program should be able to 
	determine that a failure has occurred, so
	that a new disk can be summoned.
-	When the new disk is to be put in, it shouldn't
	cost too much down time to insert it.
	I guess all the software from the good disk
	would have to be copied to the new disk before
	using it. But there are other solutions to this
	problem though - like replacing the whole unit
	with a new one, and fixing the bad one at leisure.
-	Minimum hassles with configuration etc.

There must be some people out there with experience of
both sorts of RAID.
Can anyone tell me if I would be better off with
hardware or software RAID?

The kind of machine I'm talking about here is:

800 MHz Intel
2U rack mount
2 usable PCI slots, one taken with ethernet
colour = black!
OS = SuSE 7.1
kernel = 2.4.4+
disks = 2 x 20 GByte
RAM = 128 MB

Cheers,
Alan Kennington.

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    name: Dr. Alan Kennington
  e-mail: akenning@topology.org
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    city: Adelaide, South Australia
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