Re: [reiserfs-list] ReiserFS on RAID5 Linux-2.4 - speed problem

[Edward Shushkin <edward@namesys.com>]

Rene Rebe wrote:
> 
> (Repost - since my first mail has still not arrived ...)
> 
> Hi - I need some speed tips for using ReiserFS on an RAID5 Linux-soft-raid device.
> 
> Config: AMD K6-2 350
>         3x IBM 40GB IDE discs (connected as master each to a single IDE channel)
>         Linux-2.4.1x (currently .16)
>         the discs are combined via Linux-software-RAID5
> 
> I run ReiserFS on a RAID5 (of 3 IDE disks) using the latest 2.4.(e.g.16)
> kernel for weeks. It works well except that is is painfully slow. In todays tests
> I got arround 3MB/s from ReiserFS (dd if=/home/database/some-video.avi ...) - wich
> matches exatly what I get over NFS for normal development usage, too. The IDE or
> RAID setup doesn't seem to be a problem because I get 33MB/s when I read the
> /dev/md/0 directly (dd if=/dev/md/0 ...)!

Thats odd!
I don't have three various ide-controllers to reproduce your configuration, 
but for the raid5 of 3 various scsi disks i have that the times of dd readings for 
if= /dev/sda, /dev/md0, /mnt/file_on_reiserfs_on_md0 relates approximately as 
1.5 : 1 : 1   
So the performance doesn't decrease..
What is about your speed for (dd if=/dev/hdx...)??
Can you measure this for ext2 on md0?

Thanks,
Edward.