Here my 2 cents:
Ever since I had bought a Western Digital My Cloud System with 4 TB of Backup space, I had problems with it: after some hours, the system was unreachable over the network. Several firmware upgrades later, the problem has aggravated, and the system was reachable only for 10 to 20 minutes after powering it on.
In my blog post Resolving Networking Problems (Performance Problems) of a WD My Cloud NAS System - I have summarized the measures I have taken to get it back to life.
In short: by enabling SSH and using top, I have found out that the system was in a heavy swapping mode because of missing memory, which had caused the problem on my side. I also could see that the system was spawning 10 apache2 processes, which were consuming almost 100% of the physical memory, so other processes were starved.
As a resolution, I have changed the number of apache2 processes to a reasonable number (3 in my case). Since then, the disk is silent (it was working heavily and audibly before), and the web interface responsiveness is higher than ever before.
To perform the changes, log in per SSH as root, edit the file /etc/apache2/mods-available/mpm_prefork.conf.
Before the change, I have found following relevant content in the file:
StartServers 2
MinSpareServers 2
MaxSpareServers 10
MaxRequestWorkers 10
MaxConnectionsPerChild 10000
I have changed this to:
StartServers 2
MinSpareServers 2
MaxSpareServers 3
MaxRequestWorkers 3
ServerLimit 3
MaxConnectionsPerChild 10000
This was the resolution that had helped in my case; a resolution I have not found in any of the Forum posts.
I hope this is useful information for someone.
