Subject: Bad performance, biowait on raid device
To: None <>
From: Stefan Wurstbauer <>
List: tech-kern
Date: 03/14/2006 18:09:51
Hi all,
I'm running NetBSD 3.0 on a Dell PowerEdge 4600 server. The disks are
4 scsi disks / raid 5 on a hardware raid controller, mounted as a ffs
filesystem (without softdeps). 
When I, for example, extract pkgsrc.tgz I take ages to complete.
  >time tar zxf pkgsrc-current.tar.gz
   real    113m46.454s
   user    0m6.216s
   sys     0m33.493s

Most of the time top shows biowait fort he tar process (D+)

Has anyone an idea how to improve the performance?