From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lists.gentoo.org ([140.105.134.102] helo=robin.gentoo.org) by nuthatch.gentoo.org with esmtp (Exim 4.54) id 1En4N0-0001XO-CT for garchives@archives.gentoo.org; Fri, 16 Dec 2005 01:26:50 +0000 Received: from robin.gentoo.org (localhost [127.0.0.1]) by robin.gentoo.org (8.13.5/8.13.5) with SMTP id jBG1PSB7011379; Fri, 16 Dec 2005 01:25:28 GMT Received: from wproxy.gmail.com (wproxy.gmail.com [64.233.184.201]) by robin.gentoo.org (8.13.5/8.13.5) with ESMTP id jBG1LN5K032767 for ; Fri, 16 Dec 2005 01:21:24 GMT Received: by wproxy.gmail.com with SMTP id 68so491298wri for ; Thu, 15 Dec 2005 17:21:23 -0800 (PST) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:sender:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=Oeo/5RTknLtKeUfCsTr1EwMvE4hq95EgJxbsh/JjxnIhnKdcsCfVLyNqbqUC/OkRnqUR/evmQbm/pNGO4Fsf9fDd62y0c7jBRH6wbklHzZCsmWvEHORhRw3SVK1r8BAmTjSd49571wGPN6R3EQOiBLBfOT7VM3QdS3L2bWPYx+w= Received: by 10.54.71.14 with SMTP id t14mr3025942wra; Thu, 15 Dec 2005 17:21:22 -0800 (PST) Received: by 10.54.69.9 with HTTP; Thu, 15 Dec 2005 17:21:20 -0800 (PST) Message-ID: <7573e9640512151721m5624282fge53499c2f3db01b2@mail.gmail.com> Date: Thu, 15 Dec 2005 18:21:20 -0700 From: Richard Fish Sender: richard.j.fish@gmail.com To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] Software RAID Advice Needed In-Reply-To: <43A1EF2B.8090009@badapple.net> Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Disposition: inline References: <20051215215557.84137.qmail@web53909.mail.yahoo.com> <43A1EF2B.8090009@badapple.net> Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by robin.gentoo.org id jBG1LN5K032767 X-Archives-Salt: 4fa86c48-7e42-4bdb-8fc4-478312672913 X-Archives-Hash: bca63f2f2101310a27835ba5616af4ca On 12/15/05, kashani wrote: > Assuming this is a small home system I'd go with RAID 5 with maybe a > hot spare if I have more than four drives in a normal server setting > where reads happen more often than writes. That's more space with > comparable performance for anything you're likely to be doing. I would say the choice between RAID 5 and RAID 0+1 would be based upon what you are doing. Assuming a 4-disk array, RAID5 will require 2 reads and 2 writes for writing a single block of data, while the RAID0+1 array would only require 2 writes. Read performance with RAID5 should be at least 75% of the RAID0+1 setup, possibly equal depending upon the bandwidth of the PCIe bus. So if you are doing something like video streaming, RAID0+1 would be a better choice. Web browsing, email, compiling, and typical desktop use would be well suited to RAID5. Also, consider that you can mix-and-match RAID levels with different partitions. You can create a 4-partition RAID0 array for swap, a 4-partition RAID0+1 array for filesystems that experience a lot of writes (/var, /tmp, and maybe /usr/src, for example), and a 4-partition RAID5 setup for /root, /home, et al. If a disk fails, your system would likely crash (due to the swap device), but would reboot in a degraded mode (no swap, slow performance, etc). I wouldn't overdo the complexity here, but the above becomes quite a bit easier to manage if you combine RAID with LVM or EVMS to manage your filesystems. -Richard -- gentoo-user@gentoo.org mailing list