[CentOS] Upgrading drives in raid 1

Thu Jul 2 17:35:56 UTC 2009
Robert Heller <heller at deepsoft.com>

At Thu, 2 Jul 2009 13:18:43 -0400 CentOS mailing list <centos at centos.org> wrote:

> >If /dev/md1 is made out of /dev/sda2 and /dev/sdb2, it will not work,
> >as those partitions will still be the same size as they were before...
> I have md0 as the boot, md1 as the rest. Inside md1 are all my lvm
> partitons.
> The grow command is supposed to expand the size of that md1 from its current
> 200+GB to fill the rest of the 500gb drive.
> I thought you could then expand the lvm partions inside of that.
> If the grow command does not make the raid device larger, then what does it
> do?

It only works once you have replaced all of the smaller drives with
larger ones.  If /dev/sdc is your spareset drive, when you replace it
you'd partition it (manually) to have a larger #2 partition.  Then you
would fail over say sdb to sdc and make sdb the spareset drive and then
pull it and replace it with a large disk and partition it like sdc, then
you would fail sda over to sdb and replace sda with a large disk, and
partition it like sdc.  NOW you can grow the raid set & LVM vg.

> # cat /proc/mdstat
> Personalities : [raid1]
> md0 : active raid1 sdc1[2](S) sdb1[1] sda1[0]
>       104320 blocks [2/2] [UU]
> md1 : active raid1 sdc2[2](S) sdb2[1] sda2[0]
>       245007232 blocks [2/2] [UU]
> unused devices: <none>
> Thanks for the input...glad I posted before I did this.
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Robert Heller             -- 978-544-6933
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