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

Richard Tector richardtector at thekeelecentre.com
Thu Feb 12 03:57:16 PST 2009

Bradley Radjoo wrote:
> Greetings,
> 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
> second....
> 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

in /boot/loader.conf and reboot.

Assuming you are using SATA drives, the write cache is disabled by 
default. This reenables it. The mpt manpage holds more information.



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