Time Machine on a Synology NAS

October 17, 2012 at 11:14 pm 1 comment

Time Machine is something that seems to give the NAS user fits.

Soon after Time Machine was available, I did some hacks to make it work across a network on a Sparse disk.  After a while, various NAS makers officially supported Time Machine, but the support wasn’t very good.

The ReadyNAS method, for instance, allows you to select a max size for your TM backups.  Unfortunately, it seems to be a max for all the machines you backup to the NAS.  At one point, I read one tip that said to start with your smallest capacity drive, and set your limit to the amount you wish that backup to be restricted to.  Next, get that Time Machine job running, so it creates the sparse file (limited to the size you selected).  Then, go back and increase the size for the next machine you want to backup, and repeat this process for each machine.  This supposedly sets the max size for each sparse file to the size you specified in the ReadyNAS Web interface as you created each file.  In practice, I’m not sure this works very well  because my Mac still showed more space available that he was theoretically limited to.

I read that the best method with a Synology NAS was to split your drive space up into multiple volumes, and dedicate a single volume to Time Machine.  I don’t quite see the logic in doing this, as you are taking one of the main advantages of a NAS (gobs of storage, all in a big pool), and splitting it up.

The best method I found for doing this (with DSM 4.1, in my case) is to simply create a new Shared Folder, which I called “Time Machine”.  Then, set it as your Time Machine share (under Mac File Service on the Win/Mac/NFS panel).  Finally, go to the Users page, and add a new user for each machine you wish to backup.  I named them after the machine they were created for, with “TM” on the end of the machine name.  While creating the users, make sure not to put them in the Administrators group, and set the quota for the amount of space you wish to have as the Max for that machine.  I generally set this to about twice the capacity of the machine, but I’ve seen suggestions of three times or more.

With this method, each machine sees only the amount of space available for backups that you’ve specified as their Quota.  Since it’s all on one Volume, whatever you haven’t used for TM backups is available for use by the other shares, so you aren’t locking yourself into a size, as you would be if you hard defined a volume for TM backups.

One Note:  It appears that the Quotas define GB based on 1024, instead of 1000.  This means that if you specify a quota of 700 GB, you’ll end up closer to 750 GB shown as available on your Mac.


Entry filed under: Networking.

Why I am moving to a Synology DS1512+ And the Reaver comes for you…r wirless network

1 Comment Add your own

  • 1. jcierra  |  March 25, 2013 at 8:33 pm

    You are right about keeping a large pool of storage instead of splitting it up. Since you already bought an expensive machine, let it do the work instead of you.


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