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 13:42:20 +0100 Message-ID: <4F39052C.1080409@westcontrol.com> References: <4F35E925.6000003@hardwarefreak.com> <4F38FD5D.1010201@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: <4F38FD5D.1010201@hardwarefreak.com> Sender: linux-raid-owner@vger.kernel.org To: stan@hardwarefreak.com Cc: CoolCold , Linux RAID List-Id: linux-raid.ids On 13/02/2012 13:09, Stan Hoeppner wrote: > On 2/12/2012 2:16 PM, CoolCold wrote: >> First of all, Stan, thanks for such detailed answer, I greatly appreciate this! > > You're welcome. You may or may not appreciate this reply. It got > really long. I tried to better explain the XFS+md linear array setup. > >> 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) > > So you need LVM for snaps, got it. > >> 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 no longer the case as of kernel 2.6.35+ with Dave Chinner's > delayed logging patch. It's enabled by default in 2.6.39+ and XFS now > has equal or superior metadata performance to all other Linux > filesystems. This presentation is about an hour long, but it's super > interesting and very informative: > http://www.youtube.com/watch?v=FegjLbCnoBw > OpenVZ is great for many purposes, but one unfortunate point is that because it is based on patches to a number of key parts of the kernel, it is only rarely re-synced to new kernels. It is currently stuck on 2.6.32, which means he can't use this feature (and nor can I - I also use OpenVZ and sometimes XFS, though I'm not too bothered about squeezing the last drops of performance out of the system).