smb4.conf

[global]
# adjust this to your network/netmask
remote announce = 172.16.100.0/24
security = user
encrypt passwords = yes
 
ea support = No
kernel share modes = No
mangled names = no
path = /usr/local/timemachine/%U
posix locking = No
read only = No
smbd max xattr size = 2097152
 
vfs objects = catia fruit streams_xattr zfsacl
# these are the objects which did not work on my Samba instance
# tmprotect shadow_copy_zfs ixnas zfs_core aio_fbsd
 
fruit:time machine max size = 800G
zfs_core:zfs_auto_create = yes
fruit:locking = none
fruit:time machine = yes
fruit:resource = stream
fruit:metadata = stream
fruit:encoding = native
nfs4:chown = true
ixnas:dosattrib_xattr = false
 
[tm]
comment = Time Machine

my share looks like this:

[timemachine]
        comment = Time Machine
        create mask = 0600
        directory mask = 0700
        path = /mnt/10tb/shares/timemachine/
        read only = No
        spotlight = Yes
        vfs objects = catia fruit streams_xattr
        fruit:time machine = yes
        fruit:aapl = yes

I have this for use with 4.16.11 - I note I am missing fruit:aapl = yes as seen in the config from @RealKelsar

[16:22 tc dvl ~] % cat /usr/local/etc/smb4.conf
# This instance is used only for Time Machines. Nothing else.
# from https://bsky.app/profile/sweordbora.hausen.com/post/3kafje4ovq52z

[global]
remote announce = 203.0.113.255
security = user
encrypt passwords = yes

ea support = No
kernel share modes = No
mangled names = no
path = /usr/local/samba/tc/%U
posix locking = No
read only = No
smbd max xattr size = 2097152

vfs objects = catia fruit streams_xattr
# these are the objects which did not work on my Samba instance
# tmprotect shadow_copy_zfs ixnas zfs_core aio_fbsd

fruit:time machine max size = 1T
zfs_core:zfs_auto_create = yes
fruit:locking = none
fruit:time machine = yes
fruit:resource = stream
fruit:metadata = stream
fruit:encoding = native
nfs4:chown = true
ixnas:dosattrib_xattr = false

[tm]
comment = Time Machine