You will have to experiment. Don’t think WD has an official list of supported hubs or even supported USB drives. Further I don’t think there is a set number of supported drives the My Cloud will support being connected at the same time. The My Cloud (at least with the v4.x firmware) has known issues with some USB external hard drives. In some cases the drives are seen but do not properly mount. My wild speculative guess is that the firmware has trouble with the way certain USB external hard drives are formatted and while it will see them attached will not properly mount them. I discussed my issues with one particular hard drive that was seen but not mounted starting with this post in another thread.
Using an old Belkin USB 2.0 7 port hub I have four hard drives and three flash drives connected to it… From the Dashboard USB status icon it indicates the following:
Prolific Technology Inc. USB-SATA Bridge
200 GB Free of 500 GB
Toshiba External USB 3.0
330 GB Free of 1 TB
05e3 USB TO IDE
9.3 GB Free of 40 GB
Western Digital External HDD
84 GB Free of 320 GB
SanDisk Cruzer
23 GB Free of 32 GB
SanDisk Cruzer*
0 KB Free of 0 KB
SanDisk U3 Cruzer Micro
3 GB Free of 4.1 GB
*I think the reason why that one SanDisk Cruzer reads 0k is because its formatted as a Ubuntu OS boot device.
For some reason the Share list (and when looking at the Shares with Windows File Explorer) only five of seven Shares are listed for the seven attached USB devices. One of the hard drives, the WD My Passport drive, keeps throwing the following Notification message in the Dashboard and is one of the two not shown/seen as a Share:
Unsafe device removal
A USB device (vendor: Western Digital, model: External HDD, serial number: 57442D5758485A3038363338383632) was removed without being ejected possibly affecting data on share MYPASSPORT.
Friday, April 01, 2016 4:30:59 AM Code 1123
