From owner-freebsd-questions@FreeBSD.ORG Fri Dec 30 13:12:36 2011 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 E246F106567D for ; Fri, 30 Dec 2011 13:12:36 +0000 (UTC) (envelope-from freebsd-questions@herveybayaustralia.com.au) Received: from mail.unitedinsong.com.au (mail.unitedinsong.com.au [150.101.178.33]) by mx1.freebsd.org (Postfix) with ESMTP id 8F4898FC26 for ; Fri, 30 Dec 2011 13:12:36 +0000 (UTC) Received: from laptop1.herveybayaustralia.com.au (laptop1.herveybayaustralia.com.au [192.168.0.179]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by mail.unitedinsong.com.au (Postfix) with ESMTPSA id 138CF5C24 for ; Fri, 30 Dec 2011 23:25:03 +1000 (EST) Message-ID: <4EFDB7FD.4040606@herveybayaustralia.com.au> Date: Fri, 30 Dec 2011 23:09:17 +1000 From: Da Rock User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:7.0.1) Gecko/20111109 Thunderbird/7.0.1 MIME-Version: 1.0 To: freebsd-questions@freebsd.org References: <1325229204.34713.YahooMailNeo@web140405.mail.bf1.yahoo.com> <20111230124153.GA18989@slackbox.erewhon.net> In-Reply-To: <20111230124153.GA18989@slackbox.erewhon.net> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: Why do I feel like compact flash is more reliable than SSD ? 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: Fri, 30 Dec 2011 13:12:37 -0000 On 12/30/11 22:41, Roland Smith wrote: > On Thu, Dec 29, 2011 at 11:13:24PM -0800, UFS User wrote: > >> I have run a lot of different FreeBSD systems off (fileservers, firewalls, >> routers, etc.) off of compact flash cards[1] and have never had a CF part >> fail. >> >> Most of these were read-only mode, but some of them were left mounted 'rw' >> for years (with no swapping, of course). The bottom line is, they never >> failed, and some were (and are) in the field for over 8 years now. >> >> But everyone I know (including me) has had an SSD fail, usually with no >> explanation. > It seems that unlike disk drives, SMART doesn't really give you a warning with > SSDs. > > But as a counterpoint, who hasn't ever had a harddrive fail? And there might > be some negativity bias [http://en.wikipedia.org/wiki/Negativity_bias] at work > here too. > >> So is this just chance, or ... are CF cards really a lot more reliable than >> SSD ? > Although I've been looking at SSD's, I've held off for now because of cost and > small disk sizes. But concrete data is relatively scarce, probably due to the > fact that SSD's haven't been available _that_ long. > > There are several studies available for harddisks, e.g. from google > [http://labs.google.com/papers/disk_failures.pdf] and Carnagie Mellon [http://www.usenix.org/events/fast07/tech/schroeder/schroeder_html/index.html]. > Generally, more disks fail as they age. > > But studies concerning SSD's seem to be almost nonexistant. The most interesting > inventarization I found was on Tom's Hardware > [http://www.tomshardware.com/reviews/ssd-reliability-failure-rate,2923.html]. > Some interesting quotes covering the main points; > > Even though our data set is one-twentieth the size of previous studies on > hard drives, our information starts to suggest that SLC-based SSDs are no more > reliable than SAS and SATA hard drives. > ... > Our data center survey exclusively covers Intel SSD failure rates because > those are the drives that big businesses currently trust the most. > ... > Should you be deterred from adopting a solid-state solution? So long as > you protect your data through regular backups, which is imperative regardless > of your preferred storage technology, then we don't see any reason to shy away > from SSDs. > > Currently SSD's are too small for my taste. But when that changes, I'll > seriously consider switching to an SSD with an equal sized HDD for nightly > backups. I'd only consider them in laptops- and even then I don't see too much difference in power use, only shock resistance. And I'd back them up to the network anyway- store most of the data on a fileserver and only copy what was being worked on to the lap. I can't see too much point otherwise, 60Gb is reasonable for a desktop with the usual suspects and is reasonably priced (not too over the top anyway...).