A while ago I decided to setup my TimeMachine backup of my MacBook Pro to an external USB drive, essentially to save space on the main Synology volume and also to decrease those disk’s activity, and here’s how I did it.
For future reference, this applies to:
- Synology DSM 6.1.x
- MacOS 10.12.4
The first thing is to connect an external USB drive to the NAS, both of which support USB 3.0. After that, if the drive was correctly recognised by the system, it will appear in the menu bar’s eject quick menu. But we need to open Control Panel > External Devices and format the drive, in case it’s not ready for use.
I used EXT4 both for better compatibility and because I won’t be using it anywhere else other than the Synology. The NAS will only offer you the option of formatting to EXT4 and FAT32, but it will also recognise exFAT if you purchase the license for it in the Package Center (as you can see in the previous screenshot).
From there we need to setup the TimeMachine folders. For that we go to Control Panel > File Services > Advanced tab. Inside you’ll find at the bottom of Bonjour settings the button to “Set Time Machine Folders“. Pressing that will give us a direct selection of all the available file shares, of which we will select usbshare1.
Notice that I’m not using AFP anymore. Newer versions of both macOS and DSM give preference to using SMB, and it is more stable.
You might also check user permissions for the user that is going to be used to connect to the TimeMachine service.
And that should be enough to get you going! Open TimeMachine on your Mac, add a new drive and it should list the network share usbshare1 instantly. Press Use Disk and you’re good to go!