mauromol wrote:> This problem is most serious when you attach a USB drive with a lot of files in it: in my tests, the My Cloud became so unresponsive that it was not accessible in any way (web UI, SSH, etc.) during the scanning process (for instance, it’s in this situation in this exact right moment and it has been doing this for hours now… I will leave it all night long and see tomorrow…) and before moving video files from the USB drive to the My Cloud itself using a third PC, the scanning process on USB drive connection even lead to out-of-memory errors that caused the Linux kernel to kill some processes, like the apache2 process… the result was a dead scanning process and a My Cloud drive accessible only via SSH.
There must be some memory leak, because before the crash I see the swap space constantly grow until the OOM happens.
I left the system there for about two whole days after connecting a 3TB USB NTFS hard disk to the MyCloud. During this period, the MyCloud unit was inaccessible: trying to connect via SSH caused the SSH client to hang undefinely, the web UI did not respond (connection timeout), no other way to know what the drive was doing. However, a continuous disk activity was in progress (I could hear the noise of the disk constantly seeking).
At last, I had to unplug the power cable, disconnect the USB drive and turn on the MyCloud again without the USB drive being connected. As soon as I plugged in the USB drive, the same thing happened again. This even if I have multimedia server disabled and, being very quick to operate before the MyCloud got unresponsive, I could disable multimedia content for the shared folder corresponding to the USB drive.
Fact is that there are some background processes in the MyCloud that still scan continuously the contents of the drive and of any connected USB drive even if all the multimedia features are disabled. In my case the USB drive had some folders used for old backups with tens of thousands files and this seemed to make the MyCloud crazy.
At last, I found the solution:
- make sure the USB drive is not connected
- start MyCloud
- connect to MyCloud via SSH
- stop the wdnotifierd service: service wdnotifierd stop
- make the change permanent (that is: let you start that service manually only when you want it, instead of automatically at system statup): update-rc.d wdnotifierd disable
- plug the USB drive
In this way you stop the process which is causing memory leaks and undefinite disk I/O when you plug a USB drive (and not only). I really don’t know what’s wdnotifierd service for… I didn’t notice any lack of functionality in my MyCloud.
Should you ever need to revert that change (i.e.: make wdnotifierd start automatically on system start), login to SSH and type: update-rc.d wdnotifierd enable
There are at least another couple of services that scan the drive in the background and may slow down transfers: wdphotodbmergerd (which I guess builds picture previews) and wdmcserverd (which I don’t know what’s for either). You may try to stop them with the service command like above to see how transfer speeds go and then decide to disable the automatic start if you see you can live without.
This applies to firmware 3.x, but it’s likely it will work for 4.x too.
Mauro
