From owner-freebsd-fs@FreeBSD.ORG Fri Feb 17 18:17:29 2012 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A6A571065703; Fri, 17 Feb 2012 18:17:29 +0000 (UTC) (envelope-from julian@freebsd.org) Received: from vps1.elischer.org (vps1.elischer.org [204.109.63.16]) by mx1.freebsd.org (Postfix) with ESMTP id 778C88FC16; Fri, 17 Feb 2012 18:17:29 +0000 (UTC) Received: from julian-mac.elischer.org (c-67-180-24-15.hsd1.ca.comcast.net [67.180.24.15]) (authenticated bits=0) by vps1.elischer.org (8.14.4/8.14.4) with ESMTP id q1HIHRrn027256 (version=TLSv1/SSLv3 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NO); Fri, 17 Feb 2012 10:17:28 -0800 (PST) (envelope-from julian@freebsd.org) Message-ID: <4F3E9A14.3070605@freebsd.org> Date: Fri, 17 Feb 2012 10:19:00 -0800 From: Julian Elischer User-Agent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X 10.4; en-US; rv:1.9.2.26) Gecko/20120129 Thunderbird/3.1.18 MIME-Version: 1.0 To: Alexander Best References: <20120217141607.GA63659@freebsd.org> In-Reply-To: <20120217141607.GA63659@freebsd.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-fs@freebsd.org Subject: Re: freebsd-swap on ssd X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 17 Feb 2012 18:17:29 -0000 On 2/17/12 6:16 AM, Alexander Best wrote: > hi there, > > putting a freebsd-ufs partition on an ssd isn't recommended, since the ufs > structure (unlike zfs e.g.) requires certain data to be continuously written to > a fixed location and thus will cause the ssd to quickly run out of write-cycles > and die. nonsense. the SSD doesn't use the same flash for the same logical locatio each time! it maps it to different locations each time. > but how about using a small ssd (approx. 10GB) as one entire freebsd-swap > partition? will this make more sense, or are there certain structures within > the freebsd-swap partition type, which also need to be continuously written to > a fixed location? small SSDs may have less wear resistance than big ones.. the cheap ones may not even use proper mapping.. > another question i'd like to ask: are there also issues with read-cycles on > ssds? because i was thinking about putting a freebsd-boot partition on an ssd > drive and only mounting it ro. this should solve the write-cycle issue in > theory. however i'm not sure, if stuff like the dirty bit or the ufs label will > also remain untouched. so even though the partition will only be mounted ro, > freebsd might still frequently write certain data to a fixed location on the > ssd drive which hosts the freebsd-boot partition. if this is the case, is there > a way of completely prohibiting any writes to a disk? will revoking any write > permissions from the device entry under /dev guarantee this, or is using a any > device 100% ro under freebsd impossible (unless it has a hardware switch to > forbid writes)? yes there are small issues with read cycles but it is all hidden from you by the drive. > cheers. > alex > _______________________________________________ > freebsd-fs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" >