Re: Raidframe performances (was: Re: NFS performances)

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Tue, May 13, 2014 at 08:26:28PM +0200, Emmanuel Dreyfus wrote:
> Emmanuel Dreyfus <manu%netbsd.org@localhost> wrote:
> 
> > Right, this is not a NFS performance problem, but a RAIDframe performance
> > problem. 
> 
> I found the problem: disk cache not enabled on one of the RAID
> controllers. Now I have:
> 
> On a non RAID partition:
> # time dd if=/dev/zero of=/var/crash/z bs=1024k count=100
>     0.98s real     0.00s user     0.34s system
> 
> On a RAID partition:
> # time dd if=/dev/zero of=/home5/z bs=1024k count=100     
>     2.53s real     0.00s user     0.36s system
> 
> 
> Are the numbers reasonable?

There's still a 2.5x factor, but if it's not the same disk
it can happen.
I can also happen depending on the place of the partition on the disk
(the start of the disk can be faster than the end of the disk).

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--