I own a My Cloud EX4 which contains with four 4TB WD Red Pro drives and configured to use RAID 5. Yesterday, I found two drives were in a failed state, and I was unable to see any files on the NAS when accessing it from my PC. After some review of the situation and considerable thought I elected to reboot the NAS. The reboot achieved the result for which I had hoped. The two failed drives came online, their status as good, and the NAS kicked into a RAID rebuild. Almost immediately, I was able to access the files which I knew were on the NAS. Meanwhile, the NAS continues to rebuild and is at seventy percent complete.
While the result is what I desired, I would like an explanation as to why this would be. My first thought, and assumption when I chose to reboot, is that the drives weren’t really in a failed state but rather had gone off-line for some reason. This scenario would explain why the files were immediately available after the reboot. Likewise, I would not expect a rebuild to start or to be successful with a two-drive failure. It seems that both will be true. Again, this is all without replacing the drives.
Thus, is my initial assumption correct in that the drives went offline, shut themselves down perhaps due to a thermal shutdown or some other reason?
The second part of my query is regarding backups for the NAS. I have long desired to back up my NAS and have it nearly as good as an enterprise-class backup service. After yesterday’s “two-drive failure,” I began my pursuits with a more committed effort. I started looking at services such as Elephant Drive which I remember was an application that was on my NAS when I bought it. It does not appear to be there anymore, and I believe this must be due to some of the firmware updates that have occurred which ties to the drive to a WD MyCloud account. Perusing my account, I found that it is a mirror copy of my NAS. Consequently, I have some questions.
Is what I see in the web account an exact copy of my NAS or is it presenting a web interface of my NAS, and the files reside on my NAS?
If the former is true, then is this what has replaced the option to use Elephant Drive?
If the WD My Cloud web access is what has replaced options such as Elephant Drive, then will this suffice for my quest for an enterprise-class comparable backup service?
I hope that the answers to my latter two questions will be “yes” and, if so, then I will be evermore thankful I chose WD for my NAS. Likewise, this would imply that my files would still be available if my NAS completely offline or experienced a catastrophic failure.