From owner-freebsd-fs@FreeBSD.ORG Fri Feb 17 14:16:07 2012 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: by hub.freebsd.org (Postfix, from userid 1233) id 9433B1065679; Fri, 17 Feb 2012 14:16:07 +0000 (UTC) Date: Fri, 17 Feb 2012 14:16:07 +0000 From: Alexander Best To: freebsd-fs@freebsd.org Message-ID: <20120217141607.GA63659@freebsd.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Subject: 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 14:16:07 -0000 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)? cheers. alex