Raid5 damaged while doing expansion on EX4100

Hi all,

I had a EX4100 for last 5 years, it is really handy and I love it. It had 4x 4TB WD Red and I haven’t had any issues until I got out of space. I purchased 4x 12TB WD Red and started expansion on EX4100. It asked me to remove disk1 and I did so, and replaced with the new 12TB. It recognized the new disk and started expension on web interface, after couple of minutes I got notification that Raid5 is damaged. When I checked web UI disk2 status is Bad and now all lights for disks are red on the device.

What can I do at this point

  1. I haven’t powered off, would restart help as it just started to process expansion, or would it be better to not restart.
  2. I have old 4TB disk1 on hand, could I try to restore old disk removing 12TB one, Would that cause an issue?

What other options do I have, I have checked but I don’t see a similar issue (which is really unlucky of me if this happened to me for the first time in EX4100 life span :slight_smile: )

If I lose Raid5, anyway to restore my data as I did not think it would fail at this stage, all my data would lost.

Hi @aaslannn,

Please refer to the article of RAID Volume Damaged on a My Cloud:

Hi Keerti, I have already read through that article and many more.

The issue is somehow resolved, I was able to backup my data, I lost RAID5, I needed to rebuild RAID and copy my backup to new RAID5. Steps for any one interested or have a similar issue:

  1. After failed expansion on RAID5, I powered off EX4100 by unplugging it (as power button did not work during expansion)
  2. Removed new disk from disk1 slot
  3. Readded old disk to disk1 slot
  4. Reopened EX4100 (waited a bit as it takes a while to scan disks after power loss)
  5. Magically, I was back to where I started expansion, RAID was OK, all my data was available and only issue was expansion is still waiting for disk1 to be replaced with a new one and the light was Red on Disk1 slot. So with this state I wasn’t able to fix issue with disk2 as disk1 was already put out of RAID5 array
  6. I backed up everything while I had access to all of my data

After this magical recovery, I started testing on WD and my disks and what can I do with current state to fully recover the RAID array, and also I wanted to see what is possible for expansion.

  1. Started WD utilities on web UI to see what was wrong with my disk2, we have some testing options there.
  2. Just for a simple test, I restarted RAID5 setup which triggers a basic test on disks before buidling RAID array and then I saw the issue with Disk2 and that is for Disk2 SMART gives an error, and other disks seems OK. So it was diagnosable from the beginning.
  3. I have rebooted WD, and error gone and Disk2 was available again with Good status. And all my data was still available. Again only issue remaining RAID was in expansion state and Disk1 was not available.

Re-attempt to expand (this time RAID failed for good):

  1. As RAID was already Volume 1 expanding state, and disk1 was red, I have replaced Disk1 with 12TB new one to proceed with expansion one more time and it started expansion again.
  2. Same issue occured after 2 minutes into expansion process.
  3. This time, I tried to replace with old disk without powering off and then waited of couple of minutes
  4. Alert message(expansion failed) on led screen on EX4100 change to default My Cloud text, but all my disks were still red
  5. This time I had the option to power off EX4100 with power button and I did so
  6. After WD was back, there is no RAID configured, it showed 11.x TB of free space, so I lost RAID, even reboot of device did not helped to RECOVER so this time I lost everything. But I already backed up so no problem.

POST Failure Reborn:

  1. After I lost RAID on my second attempt, I removed all disks and put 12TB new ones and build the RAID from scratch.
  2. I attached all old disks to my PC and used Recovery Explorer RAID tool to reconstruct existing RAID structure on the disks. Just opening the tool is enough, it auto recognizes the RAID and I was able to access all my data on the tool.
  3. So I guess WD should be able also able to have this RAID recovered without losing my data. The tool did not scan, did not do 3 days of work, it just opened and loaded in 1m and my data was available on the tool.

My suggestion to WD:

  1. Initially test disks (as you do while creating a RAID array) and then start expansion process
  2. We should be able to cancel expansion somehow, it stucks and if it did not stuck, I would be able to replace disk2 and proceed with expansion later
  3. Have some basic way to recover such RAID issues, we should not pay a simple tool to access unbroken RAID array.