sustained sequential disk IO runs interactivity into the ground

[Mike Tancsa]

At 10:57 PM 20/06/2005, eng at donut.ugcs.caltech.edu wrote:
>I was doing a dd of dev/zero into a file on a UFS2 filesystem
>(softupdates disabled) on a clean 5.4-R system.

I see the same issue on RELENG_5 with IDE disk. However, on
FreeBSD nfs.sentex.ca 6.0-CURRENT FreeBSD 6.0-CURRENT #1: Fri Jun 17

No such issue against an IDE drive as well as an ARECA RAID5 array.  The 
box is quite responsive while blasting the disks

Also just tested against a RELENG_5 box and a twe RAID1 array and no 
problems. The system is totally responsive while doing So it might be the 
IDE drivers on RELENG_5 ?  Perhaps try sos at freebsd.org's backport of the 
CURRENT IDE drivers to stable.


         ---Mike