From owner-freebsd-questions Sat Jul 8 12:58: 3 2000 Delivered-To: freebsd-questions@freebsd.org Received: from implode.root.com (root.com [209.102.106.178]) by hub.freebsd.org (Postfix) with ESMTP id 5285437B532 for ; Sat, 8 Jul 2000 12:57:59 -0700 (PDT) (envelope-from dg@implode.root.com) Received: from implode.root.com (localhost [127.0.0.1]) by implode.root.com (8.8.8/8.8.5) with ESMTP id MAA27894; Sat, 8 Jul 2000 12:46:37 -0700 (PDT) Message-Id: <200007081946.MAA27894@implode.root.com> To: Emmanuel Gravel Cc: freebsd-questions@FreeBSD.ORG Subject: Re: Performance issues with dd In-reply-to: Your message of "Sat, 08 Jul 2000 12:27:20 PDT." <39678098.698CEF07@earthlink.net> From: David Greenman Reply-To: dg@root.com Date: Sat, 08 Jul 2000 12:46:37 -0700 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG >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