Using Time Machine with Network Drive
Preparing a Backup Volume
First thing you need to is to make a backup volume. You can use hdiutil on the command line if you want, but I'm gonna go with OSX's Disk Utility in this article. It's located under /Applications/Utilities. You can also find it on Spotlight. I always do that.
What you are going to create is a disk image. This disk image will act like a physical disk volume so that Time Machine can backup your data on this disk image.
Once you launch Disk Utility, click New Image to make a new disk volume.
Then the something like this pops up.
You need to set a few things here.
Save As
The important thing here is that your disk image name must include your Mac's MAC address.
For example, if your MAC address is 00:11:22:33:44:55 then your disk image name is going to be:
TimeMachine_001122334455.sparsebundle
And then you need to locate your disk image directly under the network drive that you're gonna use for backup. For example, if your network drive is mounted at /Volumes/backup then your disk image is going to be at /Volumes/backup/TimeMachine_001122334455.sparsebundle.
Don't know what your MAC address is? Go to Network Preferences. Select whatever network interface you're using. Usually Ethernet or AirPort. Click Advanced... button. And then go to Ethernet tab.
Yeah. That's your MAC address.
Or you could use ifconfig command. It's a lot easier for me.
ifconfig en0
Volume Name
It can be whatever you want. Doesn't really matter.
Volume Size
Must be larger than the hard drive on your Mac. You can exclude directories that you don't want to backup from Time Machine. Then the volume size must be larger than the size of the rest of files and directories. Disk Utility will make a disk image regardless of available space on the volume. When Time Machine attempts to backup your data, it will fail if there is not enough space on the disk image.
Encryption
(Haven't tested yet)
Image Format
Set it to be sparse bundle disk image
Changing Settings
Run the following command in Terminal:
defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1
I've been using a shared directory on a personal server through smb protocol, and that's where I'm going to locate the backup volume that I created previously. I'm pretty sure it would work with shared directories on Windows machines as well. I didn't test it though.
Click Change Disk... on Time Machine Preferences.
Then you will be able to see something like this:
Select your network drive and start backing up!