From mboxrd@z Thu Jan 1 00:00:00 1970 From: Phil Turmel Subject: Re: Raid 5 to 6 migration Date: Fri, 01 Feb 2013 13:19:23 -0500 Message-ID: <510C072B.1030108@turmel.org> References: <510C0075.9010908@turmel.org> <20130202001625.2b7d6514@natsu> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130202001625.2b7d6514@natsu> Sender: linux-raid-owner@vger.kernel.org To: Roman Mamedov Cc: Dominique , linux-raid mailing list List-Id: linux-raid.ids On 02/01/2013 01:16 PM, Roman Mamedov wrote: > On Fri, 01 Feb 2013 12:50:45 -0500 > Phil Turmel wrote: > >> On 02/01/2013 12:17 PM, Dominique wrote: >>> Hi list, >>> >>> I was wondering what would be the best way to convert a 6 hdd raid 5 to >>> raid 6. Ideally without having to reformat everything and lose all the >>> data in the process. I have backups of the data but I don't look forward >>> reinstalling everything on that server. > > ... > >> 3) Convert array to raid6 w/ "mdadm --grow --level=raid6" > > --layout=preserve will make it an order of magnitude faster. Read "man mdadm" > for more details. (And "man md" to learn about things in general.) But will leave the array "unbalanced"--the 7th drive will never be used for reads in normal (non-degraded) operation--reducing read performance. > That's all while still assuming you *can* or want to add a 7th drive. > If not, things become more complex. Indeed. Phil