From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brown Subject: Re: XFS on top RAID10 with odd drives count and 2 near copies Date: Mon, 13 Feb 2012 09:54:13 +0100 Message-ID: <4F38CFB5.3090102@westcontrol.com> References: <4F35E925.6000003@hardwarefreak.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: CoolCold Cc: stan@hardwarefreak.com, Linux RAID List-Id: linux-raid.ids On 12/02/2012 21:16, CoolCold wrote: > First of all, Stan, thanks for such detailed answer, I greatly appreciate this! > > On Sat, Feb 11, 2012 at 8:05 AM, Stan Hoeppner wrote: >> On 2/10/2012 9:17 AM, CoolCold wrote: >>> I've got server with 7 SATA drives ( Hetzner's XS13 to be precise ) >>> and created mdadm's raid10 with two near copies, then put LVM on it. >>> Now I'm planning to create xfs filesystem, but a bit confused about >>> stripe width/stripe unit values. >> >> Why use LVM at all? Snapshots? The XS13 has no option for more drives >> so it can't be for expansion flexibility. If you don't 'need' LVM don't >> use it. It unnecessarily complicates your setup and can degrade >> performance. > There are several reasons for this - 1) I've made decision to use LMV > for all "data" volumes (those are except /, /boot, /home , etc) 2) > there will be mysql database which will need backups with snapshots 3) > I often have several ( 0-3 ) virtual environments (OpenVZ based) which > are living on ext3/ext4 (because of extensive metadata updates on xfs > makes it the whole machine slow) filesystem and different LV because > of this. > This is a bit off-topic, but do you know of any way to get OpenVZ running on a kernel newer than 2.6.32? One important feature in 2.6.33 is mergeable LVM snapshots, which would be particularly useful for OpenVZ, such as when updating, upgrading or otherwise changing a virtual machine. With mergeable snapshots you could take a snapshot, apply the changes to the snapshot, and if it works you merge them back into the main logical partition. mvh., David