From my brief experience with Synology, I would like to elaborate on something Laplace noted.
Synology is not Mac-friendly. It is the antithesis of Mac-friendly if only for one reason:
The ext4 file system.
The ext4 file system disallows particular file name character combinations to the extent that many files on an HFS+ file system (i.e. Mac's) simply cannot be transferred onto the device.
Including, but not limited to, ANY invisible Mac file. Or any file with an underscore at the beginning. And the list goes on.
Why custom partitioning is not allowed is a mystery to me. If there is no way around the issue, it's a bad system for Macs, period. Anyone who tells you otherwise probably doesn't use NAS for network file storage and sharing, which is supposed to be any NAS's main job.
In summary, Synology and Mac, as they currently stand, do not mix well.
Not to mention, file names with underscores at the beginning, etc., are not too uncommon on NTFS file sytems either (i.e. Windows'). So Windows users should keep an eye out as well.