Re: Drive setup

From: Marko (
Date: 02/13/04

Date: Fri, 13 Feb 2004 06:06:11 -0800

All opinions given have accuracy, re-read the posts.
OK, I did. Take this gem:

"You can still software RAID with a raid controller :)"

Yes, but why would you want to? Honestly, I can't think
of a single reason I would ever do it, so can't see why
anybody else would.

>Hardware RAID is much better than software RAID.
>I will cite speed, CPU utilisation and efficiency as
     just some
>obvious reasons.
     Was this questioned?

Yes it was. Refer to gem statement. To me, that statement
leads you to believe that you would consider configuring THIS
machine with software RAID, foresaking the hardware controller.
>Given the choice, you would probably always create RAID5
>arrays using every disk
     This completely depends on your situation.

I agree, but we are thinking of two different things. I am
referring only to this machine and this scenario.
     How do you get the idea stripping 4 discs is faster and any
     different then striping 3 discs?

Um...massive experience? The more disks I add to a RAID
using hardware RAID and hot swap drives, the better the
performance. Without exception. I use UltraWide SCSI
160Mb/sec as a minimum. Maybe the RAID controllers
on some of the cheaper boards for IDE RAID is different?

     I also offer the solution of obtaining another drive to
     duplex a mirror (is this an onboard RAID controller like
     in a HP DL380 or something?) If so each channel is its
     own controller. Then create the array. I just rebuilt a
     corporate exchange server from a straight 5 disc raid5 to
     a duplexed mirror for boot/system and 3 drive raid5 and
     the performance is crushing the previous one.

If I read this right, your experience is with onboard IDE RAID
controllers, and not separate SCSI controllers? The ability
of IDE to handle data on a single cable is not the same as
the ability of SCSI to handle data on the same cable, given
comparable drive speeds. So yes, separating drives to
discrete IDE channels would massively improve performance.

In any case, I don't think I disagree with what you have said. I
just think we are focusing on different hardware choices.