[CentOS] Growing RAID5 on CentOS 4.6

Sun Aug 24 02:28:05 UTC 2008
Stephen Harris <lists at spuddy.org>

On Fri, Aug 22, 2008 at 03:21:51PM -0400, Stephen Harris wrote:
>   I wonder if I could boot off a Ubuntu CD or something and grow the array
>   that way.  Would be annoying (many hours of server downtime)...

In the end I booted a CentOS 5.2 DVD in "rescue" mode.  This appears to
have improved since 5.0 because that version threw up lots of I/O errors
(which is why I ran 4.x, which worked fine).

Once I loaded the modules in the right order I was able to grow the RAID5.
It took around 25 hours.  But, oddly, after the build the 5th disk was
taken offline.  The remaining 4 disks correctly maintained the data.

So then I rebooted back to the main build, re-added the disk, resized
the PV, extended the LV, resized the FS.  And now...

% df -hP /Media
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/Raid5-Media  3.6T  1.3T  2.4T  35% /Media

The RAID is still rebuilding.  In another 5 hours I should know if it's
worked properly!