[mythtv-users] Slighty OT: Software raid mdadm online capacity expansion (OCE) success

[Gene Stapp]

Just thought I'd let everyone know I was able to do a raid 5 disk 
expansion in mdadm software raid with no ill effects. I used mdadm 2.5.4 
(built from source) and supposedly it is pretty safe. Following this 
page as a guide and it worked perfectly. Took about 6 hours to reshape 
the array. From 300gb x 4 raid 5 to 300gb x 5 raid 5. No lvm just an md0 
mdadm device and I was still able to make 2 simultaneous HD recordings 
and watch an HD recording while this was going on.

page used as guide:
http://scotgate.org/?p=107#comments

for me the process was:
|mdadm --add /dev/md0 /dev/sde1|

then:
|mdadm --grow /dev/md0 --raid-devices=5

|to find details about your raid reshaping status use:
cat /proc/mdstat

to speed up reshaping use (fill in whatever speed you want where the 
100000 is. Default is 10000 :
echo -n 100000 > /proc/sys/dev/raid/speed_limit_max

The only difference for xfs is to use the:
 xfs_growfs (path to mounted raid filesystem)

Hope this is helpful as I didn't see anything in the archives on this topic,
Gene