Raid Hardware Question..

[dsr at tao.merseine.nu (dsr at tao.merseine.nu)]

On Mon, Jan 22, 2007 at 09:04:34AM -0500, Myrle A Francis 2nd wrote:
> Hi All & thanks in advance...
> 
>  I was wondering if some of the off the shelf Raid cards that you can
> get at Microcenter are able to support multible raids at once.
> 
> IE.
>   the card i looked at allows for 4 connections (ribbons) per card and
> two drives per connection (to drives per ribbon). So it can manage 8
> drives. I understand I can have 8 drives in raid 0,1 or 5, but can I
> make 2 of those drives raid 1 & then use the remainder of the drives for
> raide 5 or does one raid card only cable of 1 type of raid at a time
> (0,1 or 5)...
> 
> I hope the qestion made sense and as always thanks in advance..

You appear to be looking at parallel ATA cards.

There are two basic sorts of RAID card: one is really a software
RAID, which will be cheap, and have some provision for storing
RAID state, and will probably use a proprietary driver of some
sort to have your CPU do all its work. This sort may or may not
support having multiple kinds of RAID at once.

The other is a real hardware RAID. It will probably have a
reliable open source driver and will carry out the work itself.
It will be more expensive, but also higher performance, and it
will likely support having multiple kinds of RAID at once.

Frankly, the first sort of card is a waste of money. You can do
better with Linux software RAID and a cheap disk controller card
or two. Performance is maximized if you have one disk per
channel -- i.e. every disk is a Master. If you move to SATA,
this will happen for you automatically, as each disk has its own
cable.

For reliable hardware RAID, I like 3Ware for ATA and LSI for
SCSI.

-dsr-

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