Tern

History

2016-Jan-20 set up as Time Machine

Hardware

Hardware is a MiniITX server that used to be Bellman

The two Seagate Green 2TB drives are now striped because I need space more than reliability for Time Machine.

Changing over from mirror to stripe

It ended up on /dev/md126 (he shrugs).

mdadm --detail /dev/md127
mdadm --fail /dev/md127 /dev/sdc --remove /dev/sdc
mdadm --stop /dev/md127
mdadm --remove /dev/md127
fdisk /dev/sdb
fdisk /dev/sdc
mdadm --create /dev/md127 level=0 --raid-devices=2 /dev/sdb1 /dev/sdc1
mkfs.ext4 /dev/md127
blkid /dev/md127 >> /etc/fstab
emacs /etc/fstab

Software

# Must Haves
apt-get install emacs

Netatalk

Installing Netatalk makes Tern visible as an Apple server.

https://daniel-lange.com/archives/102-Apple-Timemachine-backups-on-Debian-8-Jessie.html

Built deb packages for netatalk from git on bellman and install packages here.

apt-get install mysql-common libcrack2 libmysqlclient18 avahi-daemon
dpkg --install libatalk16_3.1.7-1_amd64.deb netatalk_3.1.7-1_amd64.deb

emacs /etc/netatalk/afp.conf

systemctl enable avahi-daemon
systemctl enable netatalk
systemctl start avahi-daemon
systemctl start netatalk

Contents of afp.conf file

The "valid user" is the name of a user in the local passwd file on Tern.

[Global]
; Global server settings
vol preset = default_for_all
log file = /var/log/netatalk.log
uam list = uams_dhx2.so,uams_clrtxt.so
save password = no

[default_for_all]
file perm = 0664
directory perm = 0774
cnid scheme = dbd
 
[Homes]
basedir regex = /home

[TimeMachine_Swift]
path = /home/timemachine/swift
time machine = yes
vol size limit = 3000000
valid users = julie

[TimeMachine_Stellar]
# both plover and stellar get backed up here
path = /home/timemachine/stellar
time machine = yes
vol size limit = 3000000
valid users = bwilson

Time Machine, on the MAC

You have to allow TimeMachine to write to an "unsupported volume" with this command

defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1

On Stellar only, for some reason I had to manually create a sparse bundle on the server to make it work. Time Machine would not connect to Tern until I did. Then it would not use the bundle and I deleted it. Read "Note" below. Crazy. Connect to server from Finder. Swift and Plover had no problems creating their own bundles. Then in Terminal,

hdiutil create -size 300G -type SPARSEBUNDLE -verbose -fs HFS+J -volname "Time Machine" /Volumes/Timemachine_Stellar/stellar.sparsebundle

The SPARSEBUNDLE type means the filesystem will grow in 1M pieces, it won't immediately allocate 300GB. 300GB is the limit and you can resize it later if you need to. Stellar has a 256GB drive and right now has 115GB on it. After executing this command, the empty bundle consumed 430M of space. I remember when 430M was a huge amount of space. :-)

Note on filenames First I mimicked what I saw created by Plover: Plover.sparsebundle. I created Stellar.sparsebundle and ran Time Machine. It smiled and happily accepted that as a destination and immediately created 'stellar.sparsebundle' next to it. I think this is a screw up waiting to bite me, so I shut the Time Machine backup down, removed both bundles from the server with "rm -rf", revised the above sample command and created 'stellar.sparsebundle'.

NOW it's busily creating "stellar 1.tmp". Sigh, seems very Mac-ish. I wonder if that's good or bad. I will let it play and go do something else. This Mac is backed up to an external drive right now anyway so I can't think of any unbearable worst-case scenarios.

I am thinking about what a great program 'rsync' is...

After the "preparing" stage it renamed the folder to "stellar 1.sparsebundle", apparently ignoring the one I created. When it's done backing up I will nuke the one I created manually and see if it remains happy.