From owner-freebsd-current@FreeBSD.ORG Mon Dec 20 23:39:40 2010 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: by hub.freebsd.org (Postfix, from userid 1233) id 8D5771065670; Mon, 20 Dec 2010 23:39:40 +0000 (UTC) Date: Mon, 20 Dec 2010 23:39:40 +0000 From: Alexander Best To: Chuck Swiger Message-ID: <20101220233940.GA77618@freebsd.org> References: <20101220231005.GA68477@freebsd.org> <3B3E7B72-C7C6-46F4-9DD9-0D82194FE068@mac.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3B3E7B72-C7C6-46F4-9DD9-0D82194FE068@mac.com> Cc: freebsd-current@freebsd.org Subject: Re: two ata write chaching request X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 20 Dec 2010 23:39:40 -0000 On Mon Dec 20 10, Chuck Swiger wrote: > On Dec 20, 2010, at 3:10 PM, Alexander Best wrote: > > 1) write caching to be turned on and off for individual hdds > > (i.e. hw.ata.X.wc) and > > 2) to be able to turn write chaching on and off on the fly. > > NetBSD's dkctl allows one to enable and disable read or write caches on a per-device basis, on the fly. Presumably atacontrol or whatever the new ada / ACHI driver uses for control would be the FreeBSD equivalent.... actually i was thinking of: sysctl hw.ata.0.wc = 1 sysctl hw.ata.1.wc = 0 i'm running a ATA_CAM enabled kernel, so i'm using camcontrol. adding an option to camcontrol for to enable/disable the write cache would be nice, but having the sysctl var writable and per-device based would be nicer. cheers. alex > > Regards, > -- > -Chuck -- a13x