[OpenIndiana-discuss] Time Machine and quota limiting

[Jaco Schoonen]

Hi all,

I'm reorganizing my Home NAS (somehow it got full faster than I planned…), which I'm using for both general purpose storage and time machine backups. My server is running openindiana 151_a5 with ZFS as filesystem and netatalk as AFP-server. 

I'm wondering how others are limiting time machine quota. TimeMachine will start cleaning up old copies if the storage is almost full, but I would rather have TM start cleaning up before all my disks are full. What puzzles me is how things like compression and dedup will have an effect on reported usage and amount of free space? TimeMachine can obviously never now anything about these details, but will have some algorithms that relies on the reported disk space numbers. 

To limit TM disk-usage I have found at least 5 different options:
1) Use "zfs quota" to limit the size of the filesystem. 
2) Use "zfs refquota" to limit the referenced amount of data in the fs.
3) Use netatalk feature "volsizelimit"
4) give the sparsebundle that TM uses a maximum size (hdiutil -resize 100g)
5) Limit Timemachine at application level   (defaults write /Library/Preferences/com.apple.TimeMachine MaxSize -integer XXXX )

What are you all using and how does it work out for you? What would you recommend?

Best regards,

Jaco