Skip site navigation (1)Skip section navigation (2)
Date:      Sat, 08 Jul 2000 12:46:37 -0700
From:      David Greenman <dg@root.com>
To:        Emmanuel Gravel <egravel@earthlink.net>
Cc:        freebsd-questions@FreeBSD.ORG
Subject:   Re: Performance issues with dd 
Message-ID:  <200007081946.MAA27894@implode.root.com>
In-Reply-To: Your message of "Sat, 08 Jul 2000 12:27:20 PDT." <39678098.698CEF07@earthlink.net> 

next in thread | previous in thread | raw e-mail | index | archive | help
>I'll look into block size too. Any way to force the HD's to do write
>caching? I'm pretty sure it's implemented in hardware, but is there
>anything that would disable it?

   Oops, I said "WCD" in a previous email...it's actually WCE (write cache
enable).
   WCE is often cleared for new drives and has to be set (enabling the
write-back cache) by the user. Some newer Adaptec controllers have an option
in the SCSI BIOS setup to turn on write caching on a per-drive basis. If
your's doesn't have that, then you could edit mode page 8 using camcontrol;
something like this:

camcontrol modepage da0 -m 8 -P 3 -e

   ...and then set WCE to "1" if it isn't already that way.

-DG

David Greenman
Co-founder, The FreeBSD Project - http://www.freebsd.org
Manufacturer of high-performance Internet servers - http://www.terasolutions.com
Pave the road of life with opportunities.


To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-questions" in the body of the message




Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200007081946.MAA27894>