Linux configuration

On my linux box there is Netatalk 3.0 (AFP server). The formerly used files below

/etc/netatalk/

/etc/afp.conf

file:///etc/afp.conf
;
; Netatalk 3.x configuration file
; there has to be a closing line-feed at the end of file 
; otherwise you'll get an error:
; "iniparser: input line too long in "/etc/afp.conf""

[Global]
; Global server settings
; uam list = uams_dhx.so,uams_dhx2.so,uams_dhx2_passwd.so
uam list = uams_dhx.so,uams_dhx2.so
save password = no

[default_for_all_vol]
file perm = 0664
directory perm = 0774
cnid scheme = dbd
valid users = your_username

; [Homes]
; basedir regex = /xxxx

[TM AFP Volume]
time machine = yes
path = /mnt/VerbatimHD/tm
vol size limit = 1000000

• Beneath [Global] modules are listed that should be loaded.
• The lines below [default_for_all_vol] describes the user's read and write permissions. The user has to be the same with the same password on server and client.
• Below [Homes] home directories are defined. In conjunction with time machine this is not necessary.
• In the last paragraph time machine's share is defined: [TM AFP Volume] denominates the share. The name is arbitrary.
• This was followed by the path below which time machine saves its files and
• the maximal size (vol size limit) of space available for time machine.

Zeroconf

For zeroconf to work properly, the network settings has to be tweaked a bit. For that we open the configuration file with a text editor and make sure that the following options are correctly set:

nano -w /etc/sysctl.conf

# Source Route Verification abschalten
net.ipv4.conf.default.rp_filter = 0
# Source Validation abschalten
net.ipv4.conf.all.rp_filter = 0

The network interface has to be in promiscuous mode which mostly is the case:

ifconfig eth0 promisc

Mac configuration

I'm not sure if the following tweak is still necessary with OS X Version 10.7.5 (Lion):

$ defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1

After that don't forget to reboot your machine.

Der Sparse Bundle Trick - obsolete by now?

In my scenario I want to use an external harddrive connected to my linux server. Because the disk shall be used for other data too it is a good idea to limit the size of Time Machine's backup. This is done by creating a sparse bundle image with OSX's disk utility and copy it over to the external harddrive. Sparse bundle is an image which expands as it is filled with data. For that we need to know the name of the client and the MAC address:

hostname -s

to get the short hostname and even if your client is connected via Wifi, like mine, you need the MAC address from the ethernet interface:

ifconfig en0 | grep ether

Concatenate these two informations with an underscore, such as "name_XXXXXXXXXXXX" and you'll get the sparse bundle's filename.

hdiutil create -size 500g -fs HFS+J -type SPARSEBUNDLE \
-volname"name for backup" hostname_XXXXXXXXXXXX.sparsebundle

• size means maximal size of image (mine is 500 gigabyte),
• fs stands for file system,
• volname is just a name.
• For more informations read the manual:

  man hdiutil

Next task is to copy the newly created sparse bundle to your backup disk. Start system settings of Time Machine, point it to your afp share on the server and your initial backup should be on the way. The existing sparse bundle with its long name is going to be renamed to Hostname.sparsebundle.

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References:

Gentoo Wiki

Working with ReadyNAS

Time Machine Backups unter Ubuntu

Limit Time Machine's Backup Size