I am running macOS Server and using the Time Machine service. I have a Drobo attached via Firewire 800. I've been backing up my workstations and laptops to it for about 2 years and have built-up backups history.

I would like to add a second Drobo to the backup server to use as an additional backup destination and configure the clients to alternate backups to the two Time Machine Drobos (TM1, and TM2). However, I'd like the second backup to include the backup history form the existing Sparesebundles.

Can I simply setup the new backup destination (TM2) and copy the sparsebundles from the original backup destination (TM1) and inherit those backups? That way, if one of the Drobos dies, or one of the backups get corrupt, I will have a the backup history from my other TM storage device.

  • Are you just looking for a backup of your backups? If so, I'd do something like get carbon copy cloner and use it (or create your own rsync script) to essentially a mirror copy of TM1 on TM2.
    – NoahL
    Jun 17, 2017 at 15:40
  • 1
    No, I'm wanting to backup to two different backup locations from each client. Time Machine supports this inherently without having to use 3rd party tools. However, I don't want the 2rd backup to start fresh, rather start from where the 1st backup (copy of) left off. Jun 17, 2017 at 20:09

1 Answer 1


Yes, that it possible. I did this two or three times.

You will have to switch off the Time Machine service, then copy the backup just as if you were moving it to a new drive. The same applies to sparsebundles. Note that the copied sparsebundle will have the same maximum size as the old one, but Time Machine will increase it automatically to the size of the volume during the next backup. Finally, switch Time Machine back on, and select the new location as a backup volume.

Time Machine will check the backup thoroughly (which will take quite a long time), then accept it as base and attach further backups to it.

  • Thanks for the answer. However, not sure this applies to my situation (I'm hoping it does). This is for local backups, not backups on a macOS Server running Time Machine backup service. My backups are in Sparsebundles, not in a Backups.backupdb folder. Jun 17, 2017 at 20:07
  • Let me make sure I understand - do you mean the backups created by the TM service running on OS X server for client Macs (not the server's own backups)?
    – not2savvy
    Jun 17, 2017 at 20:11
  • That is correct. Jun 18, 2017 at 13:07
  • Adjusted my answer accordingly.
    – not2savvy
    Jun 18, 2017 at 20:07

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