In my network I have:

  • a Macbook Pro (running Lion)
  • an iMac (running Lion)

and I want to use the internal drive of the iMac as a Time Machine "target" for my Macbook Pro.

What I did is

  • create a sparsebundle on the iMac and mount it
  • share the mounted volume
  • connect my MBP to the shared volume on the iMac (with AFP)
  • tell Time Machine to use that volume to backup

My questions are

  • is it the best way to achieve what I want to do ?
  • when backup up, the MBP mount another time machine volume, because apparently it backup on a sparsebundle created in the sparsebundle which is not the simplest solution apparently. I guess this is normal behavior, but is it possible to avoid the intermediate sparsebundle, while at the same time having a control on the backup size in the iMac ?

3 Answers 3


You can set up your iMac as a fully functioning time machine server by purchasing the OSX Lion Server from the Mac App Store.

This provides you with an official method free from hacks to allow you to backup individual machines such as macbooks etc to a single target machine. I backup my Macbook Air to my iMac in this way. For extra safety, I occassionally clone off this backup volume in the iMac to an external disk and store it out of the house.

  • +1. Ideally, the system you backup to will have multiple drives in a redundancy RAID setup (for example RAID 1 or higher). This allows you to avoid manual periodic backups of the backup.
    – macaco
    Commented Oct 21, 2011 at 17:47
  • Very true if you can - try not to backup to a folder on your internal drive on your iMac, especially if that folder is just a part of your home files on your boot drive....better to have an externally attached disk. Certainly if you do store them on your internal drive as you suggest, at least clone then regularly to another disk - using Carbon Copy Cloner you can at least sync the clones to save time rather than recopying the whole volume each operation. PS, I know this isn't the cheapest method, but whether you use this or any other method, ask yourself what you are backing up is worth.
    – stuffe
    Commented Oct 21, 2011 at 18:41
  • I installed Lion Server as you suggested, indeed it is cheap/worth it for me. However could you elaborate on how I could achieve more redundancy ? I'm planning to carbon copy the whole drive of my mbp on an external drive located elsewhere (but only once a week). In addition, for the iMac: where is the backup "file" (a sparsebundle I guess) ? Should I back up the iMac or Carbon copy the sparsebundle ? Is it possible to sync the sparsebundle on an external drive using carbon copy cloner ? Thanks a lot !
    – Cedric H.
    Commented Oct 23, 2011 at 15:10
  • @Stuffe: My mbp is used for all my work and for all my photos, personnal stuff, so I would say it requires extreme care and I think it is worth investing in one more external drive to backup my iMac (or backup the sparsebundle from the iMac internal drive to an external drive as well).
    – Cedric H.
    Commented Oct 23, 2011 at 15:12

Rather than create a sparsebundle and mount it, you can mount a shared folder on another Mac using AFP.

Open Terminal and run this command editing it appropriately. Make sure the account has appropriate read/write permissions. The destination I am using is HFS+

sudo tmutil setdestination afp://user:pass@host/share

Afterwards open System Preferences and you should be able to Start the Backup. This will automatically create the appropriate sparsebundle on the destination volume.

Credit: https://discussions.apple.com/thread/4137784?tstart=0


@Cedric I would avoid keeping the Sparsebundle backups on the same hard disk as the OS,, Time Machine was updated to include Delta Backups for some file types (thouse that support versions I think, rather than all files), and as such a single change to the sparsebundle could require rebacking up the whole file each time.

My suggestion would be to get 2 external drives (of approx twice the size of your combined individual iMac/Macbook drives if possible. Set Time Machine Server to backup to one of these drives as a single partition which will create Sparebundle backups per machine backed up. Keep this drive plugged in at all times and keep Time Machine running regularly. This is your goto backup.restore drive. Then, clone this drive to another identical drive periodically (depending on how sensitive you are - bear in mind that this backup is your go to drive only if both the original machines and primary backup drive are lost at the same time, i.e. fire or theft rather than hardware failure).

There are many ways to acheive this, Carbon Copy Cloner is a nice one as it will perform a full clone the first operation, and then only do the changes in subsequent operations making it a little quicker than cloning the whole thing at one (Which I belive is what SuperDuper will do, I'm not aware unless it has been updated that it will do incrementals). I actually use Chronosync for this task, but only because I already own it, and it does the same thing (although I believe CCC is faster).

Hide this disk in a seperate location to the Time Machine Server and primary backup disk. There is no point stacking them together and losing all 3 if you get robbed). I am providing this an an answer even though the previous anser has been accepted purely because it is way to big to be a comment, please do not vote on it.

  • Addition - If you get a pair of relatively large backup disks, you can partition them along the following lines if appropriate - I use my setup as an example. I have approx 770Gb of combined storage on my Macbook Air and iMac Time Machine Server. I use a 2TB Primary backup disk that has 3 partitions, one 128GB one matching my Macbook Air, one 640Gb one matching my iMac, and the remaining 1300Gb for Time Machine backups, being approx double my requirements to allow for versions and such.
    – stuffe
    Commented Oct 31, 2011 at 17:02
  • I both TM backup to the TM partition which includes Tm backups of both machines through TM server, and Clone to the other 2 periodically using Chronosync (you can use SuperDuper, Carbon Copy Cloner, Disk Utility - whatever). I then periodically clone this backup disk in it's entirety to an identical second disk, which I keep offsite at all times it is not being used to clone. This gives be both TM backups for AdHoc restores that are bang up to date, and cloned partitions which are fairly up to date for full restore/boot purposes.
    – stuffe
    Commented Oct 31, 2011 at 17:04

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