Monday, 1 November 2021

macOS Time Machine to Synology DiskStation - have I solved it ?

 So I've been battling with Time Machine on my Mac this past few days, trying/failing to get it to backup to my Synology DiskStation Network Attached Storage (NAS).

I have an older model DS414, with ~2 TB of disk, configured as RAID, and have written about my fun with this device before including getting a nice fast Ethernet connection at 1000baseT.  

I've used this box for TM backups for a long while ....

So, for I'm not sure what reasons, this week, things started going a bit awry with backups failing to complete with: -


I have a shell script - ~/tm_logs.sh - as per this which showed: -

2021-10-30 07:47:49  Backup failed (7: BACKUP_FAILED_TARGETVOL_DISK_SPACE - Not enough available disk space on the target volume.)

which makes no sense, given how much storage I appear to have available to me: -

df -kmh /volume1/

Filesystem      Size  Used Avail Use% Mounted on

/dev/vg1000/lv  3.6T  2.0T  1.7T  55% /volume1

After much faffing about, I decided to REDO FROM START, and deleted the existing backup ( such as it was ), the shared folder AND the user ( on the NAS, by which the Mac authenticates to the Synology over SMB ).

This provided some useful inspiration: -

How do I back up files from my Mac to Synology NAS using Time Machine?

These are some of my settings: -

User & Group



File Services






Shared Folder


DSM Version


Other than that, at a friend's suggestion, I did set: -

debug.lowpri_throttle_enabled: 1

on macOS - whether/not that made any difference, I'm not sure, but I personally doubt it.

At a guess, it was a problem with the user account, perhaps a quota setting ....

Either way, so far, so good, which is nice

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