Date: Fri, 27 Jan 2012 11:26:12 +0100 From: Daniel Gerzo <danger@freebsd.org> To: <freebsd-doc@freebsd.org> Cc: pjd@freebsd.org Subject: Re: Handbook RAID1 example Message-ID: <7e043215e6cd0f2da324d6599c921fec@rulez.sk> In-Reply-To: <20120125.111625.2289296443525755896.hrs@allbsd.org> References: <alpine.BSF.2.00.1201231536490.92721@wonkity.com> <20120125.111625.2289296443525755896.hrs@allbsd.org>
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On Wed, 25 Jan 2012 11:16:25 +0900 (JST), Hiroki Sato wrote: > wb> Then add a note or warning along the lines of "The procedure > shown can > wb> only be used if the last block of the drive has not been already > wb> allocated to a partition. If the last block has been included in > a > wb> partition, back up, repartion leaving at least one unused block > at the > wb> end of the drive, create the mirror, and restore." > > I think we should rewrite this section not to create a malformed > partition table by configuring gmirror in some way. If all of > partitions are UFS, the following procedure should be safe: > > 1. gmirror label gm0 /dev/da1, and edit /boot/loader.conf to load > the kernel module. > > 2. Reboot and check if gm0 is recognized even after that (just in > case). > > 3. Create partitions in /dev/mirror/gm0 based on ones in /dev/da0. > If capacity of /dev/da0 and /dev/da1 is the same as each other > gm0 should be slightly smaller by the last sector. > > 4. Dump & restore each partition from /dev/da0* to > /dev/mirror/gm0*. > Install a boot block if necessary. > > 5. mount /dev/mirror/gm0s1a /mnt, and edit /mnt/etc/fstab to mount > gm0. Also, apply the same change to /etc/fstab in /dev/da0. > > 6. Reboot and check if gm0 is mounted as the root partition. > > 7. gmirror add gm0 /dev/da0, and wait for the rebuild. > > The primary difference between the above and one in the handbook is > to use /dev/da1 for gm0 first. By doing this, both making a backup > of /dev/da0 and repartitioning before setting up the mirror > configuration can be done virtually. The step 3 may be complex in > some cases, but I personally think partitioning /dev/mirror/gm0 by > gpart based on the existing /dev/da0 is not so difficult. Basing on my previous discussion with pjd@ I believe that this is the correct way of setting up gmirror. Pawel, could you confirm please? -- Kind regards Daniel
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