How to expand Disk size for Time Machine Backups

Wondering if someone can help me. My WDMyCloud came with 2Tb, which I was using to backup 2 Macs via Time Machine. It ran out of space (front light turned red), so I added a 3Tb USB drive through the USB port.

On my home screen at http://wdmycloud.local/ it shows there are over 3Tb of free space - wowever the Time Machine backups can’t seem to access the additional space.

What do I need to do to enable the extra space to be used for Time Machine backups? Thank you.

Generally when one adds a USB hard drive the My Cloud creates a single Share for that USB drive and it’s contents. It appears the My Cloud firmware does not automatically include that new USB drive to expand the space the Time Machine feature can use. Instead one may have to go into the My Cloud Dashboard > Settings > General > Mac Backups > Time Machine > Configure and change the Share the My Cloud will use for the Time Machine backup. This of course means the new Share (the USB drive) must be large enough to support the entire Time Machine backup.

One thing I have noticed (on a first gen single bay My Cloud) is if one enables USB Content Availability under Cloud Access in settings that the My Cloud Dashboard will include the free space on the USB hard drive into the total amount of free space available to the Time Machine Backup. Example below when compared with screen shot above.

Because of how the firmware uses a single Share to store the Time Machine backup I don’t know if it actually “spans” that Time Machine backup to the USB hard drive(s) when the space on the My Cloud internal hard drive is full. My assumption is it does not but I don’t have a Mac to test with.

One unofficial workaround to this issue is to replace the internal My Cloud hard drive with a much larger internal hard drive. There are numerous past discussions on how to do such a thing for both the first gen and second gen single bay My Cloud units.

Another workaround to this issue is to check how the Time Machine is backing up and to see if you can choose a second backup location that would reside on the USB drive Share rather than the main internal My Cloud hard drive.

First of all, thank you for responding. Unfortunately under Settings/General/Mac Backups/Configure, the Max Size slider does not recognize the extra 3TB USB drive I added - it remains limited to “1.9 TB”.

Under Settings/General/Cloud Access, USB Content Access was already on. I turned it off, then on again, no change. Under /Cloud Service/Configure/ I then clicked “Rebuild” for Content Database - but no change.

So I’m still not able to get the Time Machine Backups to recognize the 3TB USB drive I added to the 2TB internal drive.

The workaround will be to select the USB drive Share name in the Dashboard Time Machine Configuration Select a Share field. For example in my case my external USB drive Share name is Toshiba (see screenshot below). By selecting the Toshiba Share in the Select a Share field I can change the location that is the default Time Machine location on the My Cloud. The Mac Time Machine app should then start saving it’s data to the external USB hard drive rather than the Time Machine Share on the internal My Cloud hard drive. Not optimal but a workaround assuming one has a large enough external USB hard drive.

Thanks. I switched it to the 3TB drive per your instructions. However when I went to do a backup, it still used the internal 2TB drive I believe because Time Machine shows 21GB of 1.94TB available.

One thought may be to erase both drives and start over with new Time Machine backups - and see if it then recognizes both drives; Or then I can choose the larger USB drive.

However that means I lose all the backups - and an initial time machine backup takes a long time…

It’s possible one may have to check the Time Machine settings within the Mac OS to ensure it’s pointing to the correct Share. Or it’s entirely possible the My Cloud doesn’t support using a USB drive as a Time Machine Share.