Skip site navigation (1)Skip section navigation (2)
Date:      Sat, 4 May 1996 17:33:18 -0400 (EDT)
From:      Peter Dufault <dufault@hda.com>
To:        ec0@s1.GANet.NET (Eric Chet)
Cc:        asami@CS.Berkeley.EDU, dkelly@HiWAAY.net, freebsd-scsi@FreeBSD.ORG
Subject:   Re: Buffered Writes?
Message-ID:  <199605042133.RAA20783@hda.com>
In-Reply-To: <Pine.SOL.3.91.960503152557.22613A-100000@s1> from "Eric Chet" at May 3, 96 03:28:29 pm

next in thread | previous in thread | raw e-mail | index | archive | help
> 
> 
> Hello
> 	Does anybody know how to or have a utility to turn on the
> write cache on a barracuda?  I have a wide barracuda on a NCR 825 and
> would like to see if there is any performance difference.

You would use the "-e" option of the mode page editor to edit mode
page 8 and set the "WCE" (write cache enable) field to 1 to enable
write back cacheing.  Do "man 8 scsi".

This will be similar to the async update of your file system meta
data - you will introduce the problem of deferred errors, which
presently will give you an error on the wrong disk transfer and
treat the failed transfer as successful,  and you'll have the
possibility of not writing out the buffer on the disk in the case
of power failure (unless your drive can write during spindown).

-- 
Temporarily via "hdalog@zipnet.net"...

Peter Dufault               Real-Time Machine Control and Simulation
HD Associates, Inc.         Voice: 508 433 6936
dufault@hda.com             Fax:   508 433 5267



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199605042133.RAA20783>