46bb12844f
* Rewrite datactl command Prepare the target partition as part of the datactl command. Rely on partlabel for the target disk since we are always using GPT on the target disk. Use systemd and partlabel mechanism to wait and find the target data disk. Keep using the file system label to identify the source disk. Also use e2image instead of raw dd to move data. This should speed up the processes significantly. * Fix corner case when reusing same disk again
2.7 KiB
Partition
The partition layout is a bit different than the typical setup. We prefer GPT, if possible. With SoCs which don't support GPT, we use a hybrid GPT. For more details about this topic, please refer to the development documentation.
The system is designed to have as few write operations to the storage media as possible. This means that we only write during the OTA updates and 5-6 times per week on the overlay partition. The data partition receives the main I/O operations and for this reason is ideal for placing on a different drive.
A visual representation looks like this:
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| Bootloader |
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| Kernel A |
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| System A |
| |
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| Kernel B |
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| System B |
| |
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| Bootstate |
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| Overlay |
| |
...
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| Data |
| |
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Sometime the bootloader part can look different because there can be firmware or SPLs for boot the CPU on the SoC.
Data
The data partition is the only partition with real I/O. It will be expanded automatically at boot to the full size of the disk.
Using datactl to move the data partition.
In a Home Assistant OS installation, the data is stored on the /mnt/data partition of the SD card. This is the only read+write partition on the SD drive. Using the datactl move command, this partition can be moved off of the SD card onto an externally connected drive, leaving the rest of the read-only system on the SD.
The storage capacity of the external drive must be larger than the storage capacity of the existing SD card.
The command needs to be run from the host console by either connecting a keyboard and monitor or making use of the debug ssh access over port 22222. The command will not work from within an SSH add-on container.
Log in as root to get to the Home Assistant CLI and then enter login to continue to the host.
Confirm your USB SSD/HD is connected and recognized using fdisk -l.
With the drive connected, use the following command (replacing sdx with your drive, without a partition number):
$ datactl move /dev/sdx
Enter "yes" to confirm the operation. This will prepare the disk, however, the actual move will be running on next reboot. Once complete, the external drive will contain the data and will need to be plugged in to successfully boot Home Assistant OS.