Thursday, September 8, 2011

Time Machine migration. Machine rename and hardware change (using fsaclctl)

Time machine backups are associated to the Ethernet MAC address of the computer (airport MAC address in case of MacBook Air) it is backing-up, and sometimes its name.
As result when you migrate to a new computer, the old backup becomes useless.

Luckily, according to these sources, it is possible to associate the old backup disk to the new computer.
And it works!

The procedure is summarized below.
You'll need is the Ethernet MAC address of the device en0 of the new computer (the ether field reported by ifconfig):
ether 01:03:ae:d0:45:ae 

And know the name of the computer.

Running the following commands: disable the acls, modify the extended attributes, rename a directory and re-enable the acls on the backup volume.

sudo fsaclctl -p /Volumes/D/Backups.backupdb/oldname -d
sudo xattr -w 01:03:ae:d0:45:ae /Volumes/D/Backups.backupdb/oldname
sudo mv /Volumes/D/Backups.backupdb/oldname /Volumes/D/Backups.backupdb/newname
sudo fsaclctl -p  /Volumes/D/Backups.backupdb/newname -e

fsaclctl is no longer available in Snow Leopard.
So one option to recover it from a Leopard 10.5 system. The fsaclctl file in my 32bit 10.5 system had an MD5 hash: fbd9f63c17aa7e8e487f3d27c1628f7a.
Otherwise recover it from the installation disk of Snow Leopard 10.6.
A third option (which for obvious security reasons is reasonable only for me) is to download
the file from the following "data URL link" (download: which I've stored here for the posterity.

Further reading about time machine:

No comments:

Post a Comment