After 3 syncs of the raid array (15H each)
After 1 init of the array (still 15H) (using the web-interface)
And EVERY time an abnormal shutdown issue (no response from WD by the way (I know… the load of work)
I finally decided to create the array by myself:
0/ I stop the array
mdadm --stop /dev/md2
(I had to kill the pending formatting process before…)
1/ I wipe all the partition of the future array :
mdadm --zero-superblock /dev/sda4
mdadm --zero-superblock /dev/sdb4
mdadm --zero-superblock /dev/sdc4
mdadm --zero-superblock /dev/sdd4
2/ I create the array
mdadm --create --metadata 0.9 --verbose --assume-clean --level=5 --chunk=64 --raid-devices=4 /dev/md2 /dev/sda4 /dev/sdb4 /dev/sdc4 /dev/sdd4
3/ After checked the array is created and in a clean state (cat /proc/mdstat)
I reboot the Sharespace
4/ Now I am currently waiting the formatting process to finish
the formating process took 10-20 minutes (piece of cake)
I had to recreate all the shares (using the web interface) as all users were still alive.
Now I am downloading my backup : ETA 2,5 days
Conclusions (at least for me):
1/ Changing the disk could be done, but as for all raid5 array, some cares should be taken.
NEVER, EVER don’t use all the available space of the disk (to be honest, I had and still have this bad behaviour)
easy to understand example:
one array with 4 disks : 1Tb, 1Tb, 1Tb, 2Tb (yes 2).
of course the array will be 4x 1Tb leading to a 3Tb available raid5 array.
for several months (not saying some years) it works.
one day the 2Tb disk crash and is replaced by a smaller one,
lets say for example 1000Gb disk… which is in fact 0,98To…
no luck, too small, the array will never use this disk.
2/ If you have a backup, consider this seriously : maybe it is easier (and healthier) to recreate from scratch…
3/ During the process I lost the LVM architecture…
…I really don’t care, as I use ALLLLLL (yes 5!) the available space.
4/ During the process It seems I won 10Gb… (maybe the LVM arch.) from 2,70Tb to 2,71Tb
and last but don’t least.
5/ IT CAN BE DONE.
If I could have brought you some hope, I will be fine with this.
If you want some advices or a part of this experience, I’ll be glad to share