From owner-freebsd-hardware Thu Jan 30 16: 8: 3 2003 Delivered-To: freebsd-hardware@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id B8F0537B406 for ; Thu, 30 Jan 2003 16:08:02 -0800 (PST) Received: from mercury.ccmr.cornell.edu (mercury.ccmr.cornell.edu [128.84.231.97]) by mx1.FreeBSD.org (Postfix) with ESMTP id DE69643FAF for ; Thu, 30 Jan 2003 16:07:59 -0800 (PST) (envelope-from mitch@ccmr.cornell.edu) Received: from ori.ccmr.cornell.edu (ori.ccmr.cornell.edu [128.84.231.243]) by mercury.ccmr.cornell.edu (8.9.3/8.9.3) with ESMTP id TAA05158; Thu, 30 Jan 2003 19:07:58 -0500 Received: from localhost (mitch@localhost) by ori.ccmr.cornell.edu (8.12.3/8.12.3) with ESMTP id h0V07w9P006338; Thu, 30 Jan 2003 19:07:58 -0500 X-Authentication-Warning: ori.ccmr.cornell.edu: mitch owned process doing -bs Date: Thu, 30 Jan 2003 19:07:58 -0500 (EST) From: Mitch Collinsworth To: "Kenneth D. Merry" Cc: joe mcguckin , hardware@FreeBSD.ORG Subject: Re: DLT tape not streaming In-Reply-To: <20030130160348.A67127@panzer.kdm.org> Message-ID: References: <20030130160348.A67127@panzer.kdm.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hardware@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On Thu, 30 Jan 2003, Kenneth D. Merry wrote: > On Thu, Jan 30, 2003 at 14:50:45 -0800, joe mcguckin wrote: > > Our DLT-7000 tape drive does not stream continuously - there's quite a bit > > of shuttling back and forth. > > > > Are there any SCSI parameters I can tweak to improve it's performance? > > What are you using to do backups? > > dump(8) is notoriously inefficient; I would recommend using Matt Dillon's > caching tweaks to dump (use the -C option). They'll probably speed > things up somewhat. > > Another option is dumping the whole thing to a file, and then use > dd to send that dump image to the tape drive. I use that technique on a > number of machines. DLT7000 will do this if you can't feed it data fast enough. You don't need to tweak scsi you need to send the data faster. As Ken pointed out there are various ways to do this, depending on what you're trying to do. I'd suggest using amanda with a holding disk. -Mitch To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message