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

Bradley Radjoo Bradley.Radjoo at is.co.za
Thu Feb 12 06:43:23 PST 2009


Thanks very much Richard,
(They are 2 X 73Gig Ultra 320 scsi SAS drives)

BUT seems that even with the UP kernel, I still get issues..
This is what I see in dmesg :

mpt0: <LSILogic SAS/SATA Adapter> port 0xec00-0xecff mem
0xdfcec000-0xdfceffff,0xdfcf0000-0xdfcfffff irq 15 at device 0.0 on pci5
mpt0: [ITHREAD]
mpt0: MPI Version=1.5.18.0
mpt0: mpt_wait_req(6) timed out
mpt0: port 0 enable timed out
mpt0: failed to enable port 0
mpt0: unable to initialize IOC
da0 at mpt0 bus 0 target 0 lun 0
ses0 at mpt0 bus 0 target 8 lun 0

Please can you assist and advise 

-----Original Message-----
From: Richard Tector [mailto:richardtector at thekeelecentre.com] 
Sent: 12 February 2009 01:57 PM
To: Bradley Radjoo
Cc: freebsd-performance at freebsd.org
Subject: Re: Extremely slow write speeds to disk : FreeBSD 7.1 and Dell
SAS 6/iR Adapter

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	00.25.47.00
> 
> 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

Try:
hw.mpt.enable_sata_wc=1
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.

Regards,

Richard
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