From owner-freebsd-questions@FreeBSD.ORG Sun Jan 17 13:41:51 2010 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 0631D1065672 for ; Sun, 17 Jan 2010 13:41:51 +0000 (UTC) (envelope-from ronald-freebsd8@klop.yi.org) Received: from smtp-out2.tiscali.nl (smtp-out2.tiscali.nl [195.241.79.177]) by mx1.freebsd.org (Postfix) with ESMTP id 8C2D98FC0A for ; Sun, 17 Jan 2010 13:41:50 +0000 (UTC) Received: from [212.123.145.58] (helo=sjakie.klop.ws) by smtp-out2.tiscali.nl with esmtp (Exim) (envelope-from ) id 1NWV9V-0001mK-0x; Sun, 17 Jan 2010 14:26:49 +0100 Received: from 212-123-145-58.ip.telfort.nl (localhost [127.0.0.1]) by sjakie.klop.ws (Postfix) with ESMTP id 498EFF442; Sun, 17 Jan 2010 14:26:43 +0100 (CET) Content-Type: text/plain; charset=us-ascii; format=flowed; delsp=yes To: "Dan Naumov" , "Rick Macklem" , freebsd-questions@freebsd.org, freebsd-fs@freebsd.org References: Date: Sun, 17 Jan 2010 14:26:42 +0100 MIME-Version: 1.0 From: "Ronald Klop" Message-ID: In-Reply-To: User-Agent: Opera Mail/10.10 (FreeBSD) Content-Transfer-Encoding: quoted-printable Cc: Subject: Re: (SOLVED) Re: installing FreeBSD 8 on SSDs and UFS2 - partition alignment, block sizes, what does one need to know? 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: Sun, 17 Jan 2010 13:41:51 -0000 On Fri, 15 Jan 2010 17:57:03 +0100, Dan Naumov =20 wrote: > On Fri, Jan 15, 2010 at 6:38 PM, Rick Macklem =20 > wrote: >> >> >> On Tue, 12 Jan 2010, Dan Naumov wrote: >> >>> For my upcoming storage system, the OS install is going to be on a >>> 80gb Intel SSD disk and for various reasons, I am now pretty convince= d >>> to stick with UFS2 for the root partition (the actual data pool will >>> be ZFS using traditional SATA disks). I am probably going to use GPT >>> partitioning and have the SSD host the swap, boot, root and a few >>> other partitions. What do I need to know in regards to partition >>> alignment and filesystem block sizes to get the best performance out >>> of the Intel SSDs? >>> >> I can't help with your question, but I thought I'd mention that there >> was a recent post (on freebsd-current, I think?) w.r.t. using an SSD >> for the ZFS log file. It suggested that that helped with ZFS perf., so >> you might want to look for the message. >> >> rick > > I have managed to figure out the essential things to know by know, I > just wish there was a single, easy to grasp webpage or HOWTO > describing and whys and hows so I wouldn't have had had to spend the > entire day googling things to get a proper grasp on the issue :) Maybe you can copy-paste your e-mail in a wiki somewhere. And your wish =20 has come true for other peoples. Ronald. > To (perhaps a bit too much) simplify things, if you are using an SSD > with FreeeBSD, you: > > 1) Should use GPT > > 2) Should create the freebsd-boot partition as normal (to ensure > compatibility with some funky BIOSes) > > 3) All additional partitions should be aligned, meaning that their > boundaries should be dividable by 1024kb (that's 2048 "logical blocks" > in gpart). Ie, having created your freeebsd-boot, your next partition > should start at block 2048 and the partition size should be dividable > by 2048 blocks. This applies to ALL further partitions added to the > disk, so you WILL end up having some empty space between them, but a > few MBs worth of space will be lost at most. > > P.S: My oversimplification was in that MOST SSDs will be just fine > with a 512 kb / 1024 block alignment. However, _ALL_ SSDs will be fine > with 1024 kb / 2048 block alignment. > > > - Sincerely, > Dan Naumov > _______________________________________________ > 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"