Ubuntu (arm64) as a TimeMachine Server

Apple now use SMB for time machine backup, but it require F_FULLFSYNC which is not supported by most SMB servers* like Windows server or current stable version of samba.

Thanks to latest version of samba, now time machine can work with linux / unix server. But it seems there isn't so much step by step guidance for it so it caused me lots of time to build a linux server for samba.

Environment: Ubuntu Server (arm64) 18.04 LTS

1. Install dependencies

sudo apt update
sudo apt upgrade -y
sudo apt install -y acl attr autoconf bind9utils bison build-essential debhelper dnsutils \
         flex gdb libjansson-dev libacl1-dev libaio-dev libarchive-dev libattr1-dev \
         libblkid-dev libbsd-dev libcap-dev libcups2-dev libgpgme-dev libldap2-dev \
         libncurses5-dev libpam0g-dev libparse-yapp-perl libpopt-dev libreadline-dev \
         nettle-dev perl perl-modules pkg-config python-all-dev python-crypto python-dbg \
         python-dev python-dnspython python3-dnspython python3-dev xsltproc zlib1g-dev \
         libicu-dev libntirpc-dev asn1Parser

2. Download and install samba (4.12.0)

wget https://download.samba.org/pub/samba/stable/samba-4.12.0.tar.gz
tar -zxf samba-4.12.0.tar.gz
cd samba-4.12.0/
echo "^samba4.rpc.echo.*on.*ncacn_np.*with.*object.*nt4_dc" >> selftest/knownfail

CFLAGS="-I/usr/include/tirpc"          \
./configure                            \
    --prefix=/usr                      \
    --sysconfdir=/etc                  \
    --localstatedir=/var               \
    --systemd-install-services         \
    --enable-fhs                       \
    --without-ad-dc                    \
    --without-ads                      \
    --without-ldap                     &&
make && make install

3. Configure samba

sudo nano /etc/samba/smb.conf

[global]
server role = standalone server
passdb backend = tdbsam
obey pam restrictions = yes
unix password sync = yes
security = user
durable handles = yes
fruit:aapl = yes
fruit:time machine = yes
fruit:advertise_fullsync = true

[TimeMachine]
path = /Volumes/TimeCapsule
comment = Time Machine Backup Disk
browsable = yes
writable = yes
create mode = 0600
directory mode = 0700
kernel oplocks = no
kernel share modes = no
posix locking = no
vfs objects = catia fruit streams_xattr

4. Launch samba as system service

Copy the attached files (nmbd, smbd, samba) to /etc/init.d/ (or just type :) ), and register service.

cd /etc/init.d/
chmod +x nmbd smbd
sudo update-rc.d nmbd defaults
sudo update-rc.d smbd defaults
sudo update-rc.d samba defaults

5. Increase open file number limit

ulimit -n 32768
sudo nano /etc/security/limits.conf

Add line below:

*                soft    nofile          32768

6. Optional: Increase the band size of sparsediskimage

I've increased the band size to 256MB. Not sure if the open file limit 32768 is enough or not

Good luck!

costajoao/ubuntu-timecapsule.md