From owner-freebsd-fs@FreeBSD.ORG Fri Feb 17 14:27:45 2012 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: by hub.freebsd.org (Postfix, from userid 1233) id A3947106567C; Fri, 17 Feb 2012 14:27:45 +0000 (UTC) Date: Fri, 17 Feb 2012 14:27:45 +0000 From: Alexander Best To: freebsd-fs@freebsd.org Message-ID: <20120217142745.GA68510@freebsd.org> References: <20120217141607.GA63659@freebsd.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120217141607.GA63659@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 14:27:45 -0000 On Fri Feb 17 12, 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. > > 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? > > 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)? i'm sorry, if i was unprecise here. what i meant was to have a ssd drive with a freebsd-boot partition on it (which of course cannot be mounted) and an extra freebsd-ufs partition with the contents of / on it, which is the partition i'd like to only mount ro. so again the question is: will this configuration (freebsd-boot and freebsd-ufs (ro) partition) ensure that no writes to the ssd are being performed? cheers. alex > > cheers. > alex