How to install TrueNAS SCALE on a partition instead of the full disk

Install FreeNAS SCALE on a partition and create a mirror.md

Install TrueNAS SCALE on a partition instead of the full disk

The TrueNAS installer doesn't have a way to use anything less than the full device. This is usually a waste of resources when installing to a modern NVMe which is usually several hundred of GB. TrueNAS SCALE will use only a few GB for its system files so installing to a 16GB partition would be helpful.

The easiest way to solve this is to modify the installer script before starting the installation process.

1. Boot TrueNAS Scale installer from USB stick/ISO

2. Select shell in the first menu (instead of installing)

3. While in the shell, run the following commands:

   sed -i 's/sgdisk -n3:0:0/sgdisk -n3:0:+16384M/g' /usr/sbin/truenas-install
   /usr/sbin/truenas-install
   

   For TrueNAS Scale 24.10+ see this comment.

   The first command modifies the installer script so that it creates a 16GiB boot-pool partition instead of using the full disk. The second command restarts the TrueNAS Scale installer.

4. Continue installing according to the official docs.

Step 7-12 in the deprecated guide has instructions on how to allocate the remaining space to a partition you can use for data. If you are using a single drive just ignore the steps that has to do with mirroring.

Deprecated guide using a USB stick as intermediary

Unfortunately this is only possible by using an intermediate device to act as the installation disk and later move this data to the NVMe. Below I have documented the steps I took to get TrueNAS SCALE to run from a mirrored 16GB partition on NVMe disks.

For an easier initial partition please see this comment and the discussion that follows. Should remove the need to use a USB stick as a intermediate medium.

1. Install TrueNAS SCALE on a USB drive, preferrably 16GB in size. If you use a 32GB stick you must create a 32GB partition on the NVMe, wasting space that can be used for VMs and Docker/k8s applications.

2. Boot and enter a Linux shell as root. For example by enabling SSH service and login by root password.

3. Check available devices

    $ parted
    (parted) print devices
    /dev/sdb (15.4GB)  # boot device
    /dev/nvme0n1 (500GB)
    /dev/nvme1n1 (512GB)
    (parted) quit
   

If you only have one NVMe disk just ignore the instructions that include the second disk (nvme1n1). This disk is used to create a ZFS mirror to handle disk failures.

4. Clone the boot device to the other devices

    $ cat /dev/sdb > /dev/nvme0n1
    $ cat /dev/sdb > /dev/nvme1n1
   

5. Check the partition layout. Fix all the GPT space warning prompts that show up.

    $ parted -l
    [...]
    Warning: Not all of the space available to /dev/nvme0n1 appears to be used, you can fix the GPT to use all of the
    space (an extra 946741296 blocks) or continue with the current setting?
    Fix/Ignore? f
    [...]
    Model:  USB  SanDisk 3.2Gen1 (scsi)
    Disk /dev/sdb: 15.4GB
    Sector size (logical/physical): 512B/512B
    Partition Table: gpt
    Disk Flags:
   
    Number  Start   End     Size    File system  Name  Flags
     1      20.5kB  1069kB  1049kB                     bios_grub
     2      1069kB  538MB   537MB   fat32              boot, esp
     3      538MB   15.4GB  14.8GB  zfs
    [...]
   

   The other disks partition table should look identical to this.

6. Remove the zfs partition from the new devices, number 3 in this case. This is the boot-pool partition and we will recreate it later. The reason we remove it is that zfs will recognize metadata that makes it think it's part of the pool while it is not.

    $ parted /dev/nvme0n1 rm
    Partition number? 3
    Information: You may need to update /etc/fstab.
   

7. Recreate the boot-pool partition as a 16GiB large partition with a sligtly later start sector than before, make sure that it is on a sector divisable with 2048 for best performance (526336 % 2048 = 0). We also do this to make sure that zfs doesn't find any metadata from the old partition.

   Start with the smaller disk if they are not identical.

    $ parted
    (parted) unit kiB
    (parted) select /dev/nvme0n1
    (parted) print
    Model: KINGSTON SNVS500GB (nvme)
    Disk /dev/nvme0n1: 488386584kiB
    Sector size (logical/physical): 512B/512B
    Partition Table: gpt
    Disk Flags:
   
    Number  Start    End        Size       File system  Name  Flags
     1      20.0kiB  1044kiB    1024kiB                       bios_grub
     2      1044kiB  525332kiB  524288kiB  fat32              boot, esp
   
    (parted) mkpart boot-pool 526336kiB 17303552kiB
    (parted) print
    Model: KINGSTON SNVS500GB (nvme)
    Disk /dev/nvme0n1: 488386584kiB
    Sector size (logical/physical): 512B/512B
    Partition Table: gpt
    Disk Flags:
   
    Number  Start      End          Size         File system  Name       Flags
     1      20.0kiB    1044kiB      1024kiB                              bios_grub
     2      1044kiB    525332kiB    524288kiB    fat32                   boot, esp
     3      526336kiB  17303552kiB  16777216kiB               boot-pool
   

8. Now you can create a partition allocating the rest of the disk.

    (parted) mkpart pool 17303552kiB 100%
    (parted) print
    Model: KINGSTON SNVS500GB (nvme)
    Disk /dev/nvme0n1: 488386584kiB
    Sector size (logical/physical): 512B/512B
    Partition Table: gpt
    Disk Flags:
   
    Number  Start        End           Size          File system  Name       Flags
     1      20.0kiB      1044kiB       1024kiB                               bios_grub
     2      1044kiB      525332kiB     524288kiB     fat32                   boot, esp
     3      526336kiB    17303552kiB   16777216kiB                boot-pool
     4      17303552kiB  488386560kiB  471083008kiB               pool
   

9. Do the same for the next device, but this time use the same values as in the printout above. We do this to make sure that the partitions are exactly the same size. In this example the disks are slightly different in size so using 100% on the second disk would create a partition larger than the one we just created on the smaller disk.

    (parted) select /dev/nvme1n1
    Using /dev/nvme1n1
    (parted) mkpart boot-pool 526336kiB 17303552kiB
    (parted) mkpart pool 17303552kiB 488386560kiB
    (parted) print
    Model: TS512GMTE220S (nvme)
    Disk /dev/nvme1n1: 500107608kiB
    Sector size (logical/physical): 512B/512B
    Partition Table: gpt
    Disk Flags:
   
    Number  Start        End           Size          File system  Name       Flags
     1      20.0kiB      1044kiB       1024kiB                               bios_grub
     2      1044kiB      525332kiB     524288kiB     fat32                   boot, esp
     3      526336kiB    17303552kiB   16777216kiB                boot-pool
     4      17303552kiB  488386560kiB  471083008kiB               pool
   

10. Make the new system partitions part of the boot-pool. This is done by attaching them to the existing pool while detaching the USB drive.

    $ zpool attach boot-pool sdb3 nvme0n1p3
    

    Wait for resilvering to complete, check progress with

    $ zpool status
    

    When resilvering is complete we can detach the USB device.

    $ zpool offline boot-pool sdb3
    $ zpool detach boot-pool sdb3
    

    Finally add the last drive to create a mirror of the boot-pool.

    $ zpool attach boot-pool nvme0n1p3 nvme1n1p3
    $ zpool status
    pool: boot-pool
    state: ONLINE
    scan: resilvered 2.78G in 00:00:03 with 0 errors on Wed Oct 27 07:16:56 2021
    config:
    
            NAME           STATE     READ WRITE CKSUM
            boot-pool      ONLINE       0     0     0
            mirror-0       ONLINE       0     0     0
                nvme0n1p3  ONLINE       0     0     0
                nvme1n1p3  ONLINE       0     0     0
    

    At this point you can remove the USB device and when the machine is rebooted it will start up from the NVMe devices instead. Check BIOS boot order if it doesn't.

11. Now that the boot-pool is mirrored we want to create a mirror pool using the remaining partitions.

    $ zpool create pool1 mirror nvme0n1p4 nvme1n1p4
    $ zpool status
    pool: boot-pool
    state: ONLINE
    scan: resilvered 2.78G in 00:00:03 with 0 errors on Wed Oct 27 07:16:56 2021
    config:
    
            NAME           STATE     READ WRITE CKSUM
            boot-pool      ONLINE       0     0     0
            mirror-0       ONLINE       0     0     0
                nvme0n1p3  ONLINE       0     0     0
                nvme1n1p3  ONLINE       0     0     0
    
    pool: pool1
    state: ONLINE
    config:
    
            NAME           STATE     READ WRITE CKSUM
            pool1          ONLINE       0     0     0
            mirror-0       ONLINE       0     0     0
                nvme0n1p4  ONLINE       0     0     0
                nvme1n1p4  ONLINE       0     0     0
    

    But to be able to import it in the Web UI we need to export it.

    $ zpool export pool1
    

12. All done! Import pool1 using the Web UI and start enjoying the additional space.

Did you try to let it run through? I also tested this in a VM and it is working, although TrueNAS tells me wrongly that the whole disk will be used.

Did you try to let it run through? I also tested this in a VM and it is working, although TrueNAS tells me wrongly that the whole disk will be used.

It has worked for me as follows:

1. I run the command:
   sed -i ‘s/-n3:0:0/-n3:0/-n3:0:+16384M/g’ /usr/lib/python3/dist-packages/truenas-installer/install.py.
2. I install TrueNAS and do not reboot.
3. I create the partition in the remaining space and follow the steps 7 - 12 of the USB guide.

So everything is fine, thank you very much @transfairs you are a crack!

Hi @oriaj3 there is a minor mistake in your command. It has to be:
sed -i ‘s/-n3:0:0/-n3:0:+16384M/g’ /usr/lib/python3/dist-packages/truenas-installer/install.py

(-n3:0/ has been duplicated in your command)
Cheers

The suggested approach does not work for the next version (currently ElectricEel-24.10-BETA.1). Is there a simple solution for this as well?

Hi, i've update to ElectricEel-24.10-RC.2 after install.
No problem with update.
It's fresh install ?

The recommendations didn't work for me, as the trueness installer folder is an underscore rather than a dash.
sed -i ‘s/-n3:0:0/-n3:0:+16384M/g’ /usr/lib/python3/dist-packages/truenas_installer/install.py

The recommendations didn't work for me, as the trueness installer folder is an underscore rather than a dash. sed -i ‘s/-n3:0:0/-n3:0:+16384M/g’ /usr/lib/python3/dist-packages/truenas_installer/install.py

+1

For TrueNas Scale, 24.10 (Electric Eel)
Missing parts in the initial guide.
Need to use some steps from the deprecated guide.

1. Login to shell (if you are connected to the NAS with a display, press 7 to get shell with root user).
2. Use parted to edit partitions.
3. Use print list to find your boot device, for me it was /dev/nvme0n1.
4. Use select <path to your boot device>.
5. Change units using unit kiB.
6. Use print to get exact info on your boot device current partition status.
7. Find the end of the last partition in your boot device (filesystem should be zfs) - for me it was 17304576kiB
8. Create the new partition using mkpart <new partition name> <last partition end in kiB> 100%, for me it was mkpart ssd-pool 17304576kiB 100%
9. Use print to verify (You can change to unit giB for ease of use). Note your new partition number (for me it was 4)
10. quit to exit parted.
11. To create a zpool, visible for Truenas, use zpool create <pool name> <path to your boot device>p<your new partition number>. (For me it was zpool create ssd-pool /dev/nvme0n1p4 ).
12. Received an error cannot mount '/ssd-pool': failed to create mountpoint: Read-only file system
13. Verified with zpool status that my pool was created.
14. Use zpool export <pool name> to allow Truenas Web UI to see this pool.
15. Verified in the web interface I can see the new zpool in the UI (Storage page, import pool).
16. exit to exit shell.

Some extras on how to create an encrypted pool (too much details, I put here some pointers and commands but I don't have time to add the exact details):

No Encryption:

zpool create ssd-pool /dev/nvme0n1p4
zpool export ssd-pool

With Encryption

openssl rand -hex 32 > /etc/ssd-pool.key
chmod 600 /etc/ssd-pool.key

zpool create -f -o ashift=12 -O acltype=posixacl -O compression=lz4 -O dnodesize=auto -O normalization=formD -O relatime=on -O xattr=sa -O encryption=aes-256-gcm -O keylocation=file:///etc/ssd-pool.key -O keyformat=hex -O mountpoint=none ssd-pool /dev/nvme0n1p4

zpool export ssd-pool

This will require also to manually copy the key from the shell to the webui when importing the pool

Adding second SSD and mirroring both boot-pool and ssd-pool

1. Make sure what is you new device path (under /dev) - for me /dev/nvme1n1.
2. Copy partition layout: sfdisk -d <first disk path> | sfdisk <new disk path> - for me sfdisk -d /dev/nvme0n1 | sfdisk /dev/nvme1n1.
3. Attach both partitions to existing pools, using zpool attach <pool name> <partition already in pool> <new partition added to pool>, for me - zpool attach boot-pool nvme0n1p3 nvme1n1p3 and zpool attach ssd-pool nvme0n1p4 nvme1n1p4

Validation of step 2 & 3 done with parted (print list) and zpool status respectively.