Tag Archives: macos

Samba config for Apple Time Machine

Leave a reply

I’ve been using samba’s vfs_fruit module to enable backing up my mac laptop to my ubuntu-based NAS. I’ve found the configuration fiddly, and it occasionally breaks with macOS upgrades.

Anyway, I thought I would document my settings in case it helps anyone else out there. The file system backing my Time Machine share is ZFS, and I am using Samba 4.15 and MacOS Sonoma 14.4.1.

Global config

In /etc/samba/smb.conf under the [global] section, I have the following (not complete config, just the relevant settings):

protocol=SMB3
vfs objects = acl_xattr fruit streams_xattr aio_pthread
fruit:aapl = yes
fruit:model = MacSamba
fruit:posix_rename = yes
fruit:metadata = stream
fruit:nfs_aces = no
recycle:keeptree = no
oplocks = yes
locking = yes

Some comments:

  • I believe SMB3 is required – Time Machine struggles with older protocols.
  • The order of vfs objects is important – aio_pthread must go last.
  • Without aio_pthread, my backups fail while scanning. I suspect Time Machine is heavily threaded and does a lot of requests in parallel – apparently too much for a single samba thread.
  • fruit:posix_rename = yes appears to be the default and can probably be omitted
  • fruit:metadata = stream was a copy-paste and not thought through by me – I’m unsure of the implications of this

These work for me as a general set of settings for mac clients – I don’t use Windows or Linux clients often, so I don’t know how well it works for them. It’s possible some of these options are not required, as they’ve accumulated over time.

Share Config

The share itself is configured like so:

[TimeMachine NAS]
path=/pool1/backup/timemachine
comment=Time Machine
valid users = alex
writable = yes
durable handles = yes
kernel oplocks = no
kernel share modes = no
posix locking = no
ea support = yes
browseable = yes
read only = no
inherit acls = yes
fruit:time machine = yes

According to the docs, “fruit:time machine = yes” sets durable handles, kernel oplocks, kernel share modes and posix locking – you can probably omit these.

/pool1/backup/timemachine is a ZFS volume with a quota, which was set with “zfs set quota=3TB pool1/backup“. The available space is reported correctly to the client (Finder), so I’d expect it to work fine for restricting disk usage, and for time machine to manage its snapshots.

See also