From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Soltys Subject: Re: mdadm raid6->LVM->ext4 setup Date: Wed, 17 Nov 2010 00:39:45 +0100 Message-ID: <4CE31641.50909@ziu.info> References: <4CE2C8AC.7010103@geograph.co.za> <20101116221722.GC8943@maude.comedia.it> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20101116221722.GC8943@maude.comedia.it> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org Cc: zoltans@geograph.co.za List-Id: linux-raid.ids On 10-11-16 23:17, Luca Berra wrote: > On Tue, Nov 16, 2010 at 08:08:44PM +0200, Zoltan Szecsei wrote: >> >> *** Commands used: >> mdadm --create /dev/md0 --metadata=1.2 --auto=md --assume-clean >> --bitmap=internal --bitmap-chunk=131072 --chunk=512 --level=6 >> --raid-devices=8 /dev/sd[abcdefgh] >> mdadm --detail --scan >> /etc/mdadm.conf >> mdadm --assemble /dev/md0 > as i said this is not useful >> pvcreate --metadatasize 512 /dev/md0 > you should use --dataalignment, not --metadatasize, also you should Also with reference to metadatasize - keep in mind the value is rounded up to the /next/ 64k boundary (or it was a while ago, perhaps it's changed now). So in your case, 512 would really result with 576. With reference to --dataalignment - there's also --dataalignoffset option (although not really important in your setup). You might consider adjusting /sys/block//md/stripe_cache_size to higher values when you have everything set. It tends to give quite a performance boost.