---

Math home Math Dept Contact Info College of Science home Virginia Tech home Math Emporium CMDA ICAM Mathematics Education Biocomplexity Institute Privacy statement Give to VT Math Seminars and colloquia Site map People Undergraduate Program Graduate Program Research Resources

Using Time machine on the Math Backup server

Time machine can be made to manage your backupspace available on the Math Backup server. You will create a sparse bundle disk image on your Mac and then copy this to the backup server. This disk image can be encrypted if you like. Then Time machine is set to use this disk image for backups, when the image fills, it will overwrite some of the older stuff in it. You will only be able to access the Backup server when you are connected to the Virginia Tech network using a wired connection, a wireless connection, or a VPN connection.

To create the disk image you will need two things, the hostname of your mac and the MAC address of it's en0 network interface. You can get both by running a few commands in a Terminal session.

The hostname will be returned by the command hostname and usually looks something like billsmbp.local. Everthing before the .local part is your hostname.

The MAC address will be returned with the command ifconfig en0. Look for a line that contains the word ether followed by 6 pairs of hexidecimal numbers/letters separated by colons (:). The numbers/letters without the colons are your MAC address.

If the ifconfig command returned ether 34:15:9e:01:ba:dd, the MAC address would be 34159e01badd.

• As user run following command in terminal to set Time Machine to see samba shares.
  defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1
• Open Disk Utility application and create a New Blank Disk Image
  File -> New -> Blank Disk Image
  
  Make sure you set the following
  

  Name:	hostname_MAC.sparsebundle
  Format:	Mac OS Extended (Journaled)
  Encryption (if desired):	256-bit AES
  Partitions:	Single partition - Apple Partition Map
  Image Format:	sparse bundle disk image

  
  Note: hostname is the hostname of your Mac
  MAC is the MAC address of the en0 network interface.

• If you are creating an encypted disk image, you will need to choose a good password for it. If you loose this password, you will loose access to any data in stored in the image. Enter your password and make sure Remember password in my keychain is checked before clicking OK button.

  You will also need to copy this password to the System keychain so Time Machine can open the image up automatically. Run the Keychain Access application from Applications -> Utilities. Make sure the login keychain is displayed in the main window pane. Find the entry for your disk image and drag it to the system keychain in the upper left pane.

• Connect to the backup server share and copy your disk image to it.
  See File Share Help page for how to connect to the share.
  Then open a Terminal window and run the following command.
  rsync -aE hostname_MAC.sparsebundle /Volumes/backup
  hostname and MAC are hostname and MAC address of your Mac.
• Disconnect the disk image if it is currently mounted. You can also delete the sparsebundle from your Mac after it has been copied to the backup server.
• Open Time Machine Preferences, click the Choose Backup Disk button. You should see a shared drive called backup. Select and click the Use for Backup button. A window will popup where you will need to enter in your Math PID and password so Time Machine will be able to access backup.math.vt.edu. Click the Connect button.
• Click the Options button in Time Machine preferences. Exclude the system drive and anything else you don't want backed up (music, vidoes, etc...). When done click Done button.

Note: If Time Machine can not mount your backup device, it will pop a window saying the backup failed and the Time Machine icon (menubar) will have '!' in it.