Extremely slow write speeds to disk : FreeBSD 7.1 and Dell SAS 6/iR Adapter

Markus Kovero mui at mui.fi
Wed Feb 11 10:23:09 PST 2009

Hi, have you tried difference between UP and SMP kernels, years ago there
were serious performance hit with SMP-kernel and adaptec/dell perc

Markus Kovero

-----Original Message-----
From: owner-freebsd-performance at freebsd.org
[mailto:owner-freebsd-performance at freebsd.org] On Behalf Of Bradley Radjoo
Sent: 11. helmikuuta 2009 17:18
To: freebsd-performance at freebsd.org
Subject: Extremely slow write speeds to disk : FreeBSD 7.1 and Dell SAS 6/iR


Please can you assist.

I have attempted most of the popular BSD Variants such as NetBSD, Open
BSD, FreeBSD...
The only distrubution that seems to work on the is Dell SAS 6/iR Adapter
is FreeBSD 7.1
Firmware version & date : 9/29/2008

But the issue is that writing to disk is extremely slow...i.e. 14Mb per

If I install any other linux distribution, like CentOS, write speek is
the way it should be..it averages around 190Mb+ per second

I was hoping if it were at all possible for you to assist me in with a
later RAID Controller Driver for the SAS 6/iR Adapter

This is on a Dell PowerEdge R300 Server. 
BIOS Version 1.3.0
Running Raid 1 (ext3)


- Disabling ACPI does not make a difference
- I do have the latest Firmware across the hardware

Kind Regards,


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