On Sat, 05 Mar 2005 21:17:36 -0500, (Paul) wrote:

In article , Bucky
wrote:

Hey.

I have not set up my A8V system yet, and it will be a while I think.
I was wondering something. There is a parallel Raid connection on the
board, can it be used at the same time as the Sata Raid of that
controller?

In fact, can all three Raid setups be used at the same time, for 6
total Raid drives?

In theory, you could put four drives on the 20378 and two on the
Southbridge.

But the problem is, putting two parallel drives on the 20378 means
accesses to the two drives can interfere with one another on the IDE
cable and reduce your performance. If you put four drives on there,
I would pair a SATA drive with a parallel drive, to make a RAID 0
or RAID 1. If you do RAID0+1, there might be an advantage to putting a
SATA+PATA as striped pairs, then mirroring the two pairs against
one another, but there is still the potential for the IDE cable
to become a limit. For best performance, I would use no more than
two drives on the Promise 20378, and either make the drives 2xSATA
or SATA+PATA, but avoid PATA+PATA. If you don't care about
performance, any combo will work.

You can use the Promise 20378 for single drives if you want, and
there is an ATA driver available if you don't want to RAID. Since
the Promise doesn't support ATAPI, hard drives are a good thing to
use with the ATA driver. (That means your CD/DVD ATAPI devices
go on the Southbridge.)

Southbridge RAID implementations can sometimes be faster than
PCI chips, like the Promise 20378, because they may gain access
to the North-South bus, without going through a bandwidth limiting
PCI bridge. If you don't currently own the disk drives intended for
this system, buy 2xSATA and then test them on both interfaces, and
make your choice that way.

And, if you are doing a striped array, don't put the boot partition
on there, because if a stripe breaks, you won't be able to boot.
RAIDs are just a PITA to maintain, so there better be a good reason
to use one. If you use the mirror option, for example, you still
need to do backups (a power supply failure can burn both drives
and your data would still be lost). Also, a comfirmed RAID addict
would put a UPS on the computer, so a power failure can never
desynchronize a mirrored array.

HTH,
Paul

Paul, how likely can a striped RAID break, and what about just going
0+1. I know nothing about RAID really, having never used it. I have
only used SCSI non RAID. I wanted to put Windows on the RAID for
maximum speed, as my thinking was that speeding up Windows hard drive
accesses would speed up my system considerably.

Paul, could you tell me more about RAID, and/or refer me to a good
site that tells more.

I am thinking that, well, if I put my non critical stuff on a mirrored
array (and yes, I have three UPSs, they just need batteries, but they
work, APC 620 & 630s that have network connections) and on non RAID
IDE I would be covered.

What about JBOD? What is RAID 0, RAID 1, and is RAID 0+1 a
combination of striping and mirroring in some way?

Also, what is the story on RAID 5? Does it require 4 hard drives, and
if so, why didn't Asus build it into the A8V board?

Also, thank you VERY much for your excellent reply. I appreciate
everyone's help here.