If this is the wrong place for this then apologies, but I couldn't find a guide to do this on the current version of TrueNAS Core (formerly known as FreeNAS). Posting here in the hopes that I can save someone some time.

• Go to Accounts -> Users, and create a user account to use for Time Machine backups. Just leave everything other than full name, username, and password as default. For this example my TM backup user is called 'TimeMachine'.

• Go to Storage -> Pools, and click the 3 dots next to your main pool, or the pool that you want to use to hold the TM backups. Add Dataset. I called mine ‘TimeMachine’. Leave everything as default. (If you don't have any Pools AKA on a clean install just create a pool with default settings. Tip: Name it something vague like MainPool so it won't look odd when you add datasets later for a NAS share or something.)

• Now go to Sharing -> Windows Shares (SMB) (yes you use Samba for MacOS. Ignore the AFP Apple Shares option). Click Add.

• Browse the path to the location of the dataset you created in the earlier step.

• In the ‘Purpose’ drop down BE SURE TO SELECT ‘Multi-user time machine’. This will configure everything properly for you. Click Submit. When prompted to restart the SMB service do so.

• You will be asked if you wish to configure ACL for the share’s dataset. Click ‘Configure Now’.

• You will be asked to select a preset ACL or create a custom one. Select the ‘RESTRICTED’ preset. Click ‘Continue’.

• Change the user and group dropdown boxes to both reflect the name & group of the Time Machine user you created in step 1 (in this example both are called 'TimeMachine'). Be sure to check the Apply User and Apply Group checkboxes. Click Save.

• Now open Time Machine on your Mac and select ‘Select Disk’. Your TrueNAS share should be in the list. Enter the credentials for the user you created.

• Profit.

You can verify that the share is working by either waiting for the next automatic backup, or if you 'Show Time Machine in menu bar' you can click on the TM icon and select 'Backup Now'.

New guide for 22.12.1

Updated for Version 22.02.3

Hi, everybody!

First things first.

This guide created with help of my wife screaming "Do something to get rid of this annoying backup error message":) (i love my wife, don't get me wrong:)

I'm not TrueNas professional, the guide created from this and this comments from TrueNas Formus.

Sorry for grammar (ESL you know:). I will try to answer any questions you have:)

Create a Group

1. Credentials > Local Groups

1.1 Name: TimeMachine or any desired name

1.2 Check box: Allow Samba Authentication

1.3 Save

Create a User

2. Credential > Local Users > Add

2.1 Full Name: any desired name

2.2 Username: macpro or any desired name

2.3 Password/Confirm Password: Set password for user

2.4 Primary Group: TimeMachine (Select Group Created in Step #1)

2.5 Check box: Samba Authentication

2.6 Save

Create a Data Set for Time Machine

3. Storage > Add child Data Set on your main Data Set

3.1 Name: TimeMachine or any desired name

3.2 Share Type: Generic

3.3 Save

Create a Data Set for each Mac

4. Storage > Add child Data Set on your Data Set from step #3

4.1 Name: mac1 or any desired name

4.2 Advanced Options

4.4 Share Type: Generic

4.5 Save

Create a Windows (SMB) Share

5. Shares > Add

5.1 Choose path to your share from step #4

5.2 Purpose: Multi-user time machine

5.3 Check Box removed: Enable ACL

5.4 Save

5.5 on prompt: Save without restarting

Change permissions for SMB Share from step #5

Note: If your Windows (SMB) Shares list has more than 10 items, it's possible that your new TimeMachine share will not be visible. Click View Details under last share item, and change Items per page number.

6. Shares > mac1 > 3dot menu icon > Edit Filesystem ACL

6.1 Select a preset ACL

6.2 Default ACL Options: POSIX_RESTRICTED

6.3 Continue

6.4 Owner: macpro or user created in step #2

6.5 Check box: Apply User

6.6 Owner Group: TimeMachine or group create in step #1

6.7 Check box: Apply Group

6.8 Save Access Control List

Restart Windows (SMB) Share Service

7. Shares > 3dot menu icon > Turn Off Service

7.1 Wait 5 seconds (not necessary step)

7.2 3dot menu icon > Turn On Service

Connect Time Machine on your mac to new share

8. Open Time Machine

8.1 Select Disc...

8.2 Available Disks: mac1 or your SMB share created in step #5

8.3 Select and click Use Disk

8.4 Check box: Registered User

8.5 Enter user name and password you created on step #2

8.5 Happy Time Machining:)

Edit #1: Added #5.5 on prompt: Save without restarting

Edit #2: Highlighted text to be more noticeable #5.3 Check Box removed: Enable ACL

Edit #3: Guide Updated for Version 22.02.3. Changed #6.5 to Check box: Apply User, Changed #6.6 to Owner Group: TimeMachine or group create in step #1, added #6.7 Check box: Apply Group, Moved #6.8 Save Access Control List, spelling corrections, added note to step #6, Guide updated thanks to cubedgame.

I want to setup my all of my Macs to backup to a shared dataset on my Truenas.

Hi, everybody!

Decided to create a new post, due to guide is much simpler now.

Original Post

I will try to answer any questions you might have.

Prerequsite:

You need to know your mac username, not your first and last name that now days get displayed all over the macOS. How to find your user name: open terminal on your mac, type “id” and hit enter, result will be: uid=some_number(your_username)

Notes:

0.1 If your mac username longer than 16 characters (limited by TrueNAS), you need to create a separate user for backups on TrueNAS and connect to your time machine with this user.

0.1a Credential > Local Users > Add

0.1b Username: Create a username with less than 16 characters

0.1c Password/Confirm Password: Set a password

0.1c Save

0.2 Time Machine backup create a folder with your user name and backup to that folder, if you have several macs with same user name it might be a good idea to create a Dataset for each mac.

0.3 Don’t forget to setup appropriate quota size for Dataset of your individual mac shares, under Dataset Space Management.

Create a User

1. Credential > Local Users > Add

1.1 Full Name: any desired name

1.2 Username: Username on your mac

1.3 Password/Confirm Password: Set password form user on your mac

1.6 Save

Create a Dataset for Time Machine

2. Datasets > Add Dataset (Make sure your main dataset is highlighted)

2.1 Name: TimeMachine or any desired name

2.2 Share Type: Generic

2.3 Save

Create a Dataset for each Mac

3. Datasets > Add Add Dataset (Make sure your Dataset from step #2 is highlighted)

3.1 Name: mac1 or any desired name

3.2 Share Type: Generic

3.3 Save

Create a Windows (SMB) Share

4. Shares > Add Windows (SMB) Share

4.1 Choose path to your share from step #3

4.2 Purpose: Multi-user time machine

4.3 Save

4.4 On prompt: Would you like to restart SMB Service?, Select – Restart Service

4.5 ACL Editor will pop-up, click on Dashboard.

Connect mac to Time Machine share

5. Open Time Machine

5.1 Select Disc...

5.2 Available Disks: mac1 or your SMB share created in step #4

5.3 Select and click Use Disk

5.4 Check box: Registered User

5.5 Password – your mac password

5.5 Done! :)