From owner-freebsd-questions@FreeBSD.ORG Tue Jun 17 17:44:53 2008 Return-Path: Delivered-To: freebsd-questions@FreeBSD.ORG Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 316A41065679 for ; Tue, 17 Jun 2008 17:44:53 +0000 (UTC) (envelope-from chris@vindaloo.com) Received: from corellia.vindaloo.com (corellia.vindaloo.com [64.51.148.100]) by mx1.freebsd.org (Postfix) with ESMTP id F03F38FC2C for ; Tue, 17 Jun 2008 17:44:52 +0000 (UTC) (envelope-from chris@vindaloo.com) Received: from kessel.vindaloo.com (unknown [172.24.145.71]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by corellia.vindaloo.com (Postfix) with ESMTP id C68225D71; Tue, 17 Jun 2008 13:25:39 -0400 (EDT) Message-Id: From: Christopher Sean Hilton To: freebsd-questions@FreeBSD.ORG, roberthuff@rcn.com, chris@vindaloo.com In-Reply-To: <200806171540.m5HFe92o057907@lurza.secnetix.de> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (Apple Message framework v924) Date: Tue, 17 Jun 2008 13:25:40 -0400 References: <200806171540.m5HFe92o057907@lurza.secnetix.de> X-Mailer: Apple Mail (2.924) Cc: Subject: Re: Replacing tape changer with USB disk drives. X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 17 Jun 2008 17:44:53 -0000 On Jun 17, 2008, at 11:40 AM, Oliver Fromme wrote: > Wojciech Puchar wrote: >>>> >>>> you must have something wrong. my USB drive gets 27MB/s. yes this >>>> 480Mbit/s is USB isn't real, but half of it is. >>> >>> I agree. >>> Want to take this private and help figure out what's wrong? >>> :-) >> >> i simply have no idea why it could work so slow. > > Cheap controller in the USB enclosure. I've used quite > a few USB enclosures in the past years, and there are > significant performance differences. As a rule of thumb, > the cheaper the box, the slower it is. Of course there > are exceptions to that rule. > > By the way, for backup purposes I use a hot-swappable > IDE drive frame. The one I use is PATA (UDMA-133), but > there are also ones for SATA. It's much faster than > USB and more reliable. You can use atacontrol(8) to > attach and detach the drive while the system is running. > (For that to work reliably, the frame must be the only > device on its channel, i.e. no slave, in the PATA case.) > > Best regards > Oliver > I get good speeds from USB but they are bursty. I have a pair of identical controllers and both are USB/Firewire. Both have different brands and sizes of disk drive. Could the drive be part of the problem? One is connected via Firewire and doesn't have the bursty speed issue. I've only got it with USB. The poster who mentioned that I'm only looking for a backup against catastrophic disk failure is spot on. Offsite backup is something I'll work out down the road. Chris Hilton e: chris|at|vindaloo| dot|com ---------------------------------------------------------------------------- "The pattern juggler lifts his hand; The orchestra begin. As slowly turns the grinding wheel in the court of the crimson king." -- Ian McDonald / Peter Sinfield