[Samba] Mac Time Machine backups

[Phil Endecott]

Thanks torch & Louis for your comments.

I'm using the standard Debian buster packages.  I don't think
I have any need for Spotlight; this is a pure Time Machine backup
server.

It seems that it works without any explicit Avahi configuration,
though I need to set "mdns name = mdns" in order to get the
hostname in lower case in Finder.

Here is what I am now using:

# This configuration was based initially on the following:
# https://www.reddit.com/r/homelab/comments/83vkaz/howto_make_time_machine_backups_on_a_samba/
# Then feedback in this thread:
# https://lists.samba.org/archive/samba/2020-January/227885.html

# The reddit thread included an Avahi configuration fragment, but
# that is not needed; Samba manages this itself.

[global]

obey pam restrictions = yes
dns proxy = no
disable netbios = yes
smb ports = 445
vfs objects = catia fruit streams_xattr
server min protocol = SMB2
use sendfile = yes
fruit:copyfile = yes
mdns name = mdns

# Disable printers:
printcap name = /dev/null
load printers = no

# Logging:
# %m expands to client machine's name:
log file = /var/log/samba/%m.log
# Hmmm, is this working correctly?  See below about %m.
# Smaller than the default.  In kB.
max log size = 1000

# This sets the icon that appears in the Finder on the Mac.
fruit:model = RackMac
# See /System/Library/CoreServices/CoreTypes.bundle/Contents/Info.plist
# Options include RackMac, TimeCapsule, possibly "External Disk"
# (Hmm, except changing it to TimeCapsule didn't work...)


[TimeMachine]
# Hmm, could use the machine name %m rather than the user name %U here.
path = /srv/timemachine/%U
# Or can I?  There are comments in the smb.conf man page about %m not
# working on port 445, which is what is set above.

# Note sure about this; it's saying that the only valid username is the
# username that the client is trying to use.  How is that different from
# saying all users are valid?
valid users = %U

# Not the default:
writable = yes

# Need this!
fruit:time machine = yes