Subject: Re: twe status queries?
To: der Mouse <mouse@Rodents.Montreal.QC.CA>
From: Frank Naumann <>
List: tech-kern
Date: 12/02/2005 20:25:55

> However, I'm seeing a tremendous performance difference between ld0 and
> ld1.  I have a disk exerciser program; when I run it on ld0, it runs at
> a particular speed; on ld1 - in the same way - it runs at about 15% of
> that speed.  Yes, that's 3/20 the speed - almost an order of magnitude.
> At first I thought it might be that ld0 had priority over ld1, because
> they were running simultaneously, but when the ld0 run finished, the
> ld1 run didn't speed up any.

What exact escalade raid controller do you have? The performance 
difference is normal for the escalade 7000/8000 series. This is because 
Raid5 is accelerated by the so called R5 fusion technology on this 
controller (hardware XOR engine or something like that). The problem is 
that the escalade 7000/8000 can only accelerate one Raid5 array with this 
technology (so additional Raid5 arrays are much slower). Btw. this is 
mentioned in detail somewhere in the escalade users manual.

Btw. you can use Raid 10 instead :-)