From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Soltys Subject: Re: RAID on partitions and partitions on RAID Date: Sun, 29 Jul 2007 21:11:07 +0200 Message-ID: <46ACE64B.6030801@ziu.info> References: <46ABAC5A.2000103@ziu.info> <46ABB830.1000204@ziu.info> 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: Cry Regarder Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids Cry Regarder wrote: > > Thanks! A couple questions: > > 1. Are you sharing that spare with an other array? If not, why not do a raid-6 > instead of a raid-5? > No, the spare is not shared. Now that I think about it and you reminded about raid-6... I can think of one small plus of my setup - that spare is not spinning (it's stopped with sdparm -C stop). So the disk should be in almost unused condition if the need for it arrives. Excluding vibrations from the rest of the disks, and barely active electronics. > 2. I noticed that you built your raid partitions on corresponding disk > partitions. Why do that instead of making one monolithic raid volume and then > partitioning that into the desired pieces? > few reasons: 1) I wanted /boot out of any raid 2) I wanted LVM for some of the partitions 3) I prefered regular mbr on the whole disks. 4) I wanted properly aligned XFS, so I can use its su/sw options Alternatives: - create separate md0 (for lvm) md1 (for xfs), but it seemed wrong when there is support for partitionable arrays - or I could just put everything on lvm and don't bother with xfs alignment. All things considered, it looked like a decent compromise. Of course, I'm open for suggestions. > > 1. Adjust the partition table on each of the component disks so that I can > assemble the drives from /dev/sd?1 instead of /dev/sd? > No can do here, afaik. When you assemble from /dev/sd? , there're no partitions to start with on those disks. Either way, I'm not aware of any tools allowing - shrink raid, shift it, create fitting mbr ... > 2. Adjust my /dev/md0 so that it is partitioned into /dev/md0_1 /dev/md0_2 or > something of that ilk. > No idea if you can easily switch from non-partitionable to partitionable raid.