| ## Basic setup |
| 1. Install `zfs-dracut` |
| 2. Set `mountpoint=/` for your root dataset (for compatibility, `legacy` also works, but is not recommended for new installations): |
| ```sh |
| zfs set mountpoint=/ pool/dataset |
| ``` |
| 3. Either (a) set `bootfs=` on the pool to the dataset: |
| ```sh |
| zpool set bootfs=pool/dataset pool |
| ``` |
| 4. Or (b) append `root=zfs:pool/dataset` to your kernel cmdline. |
| 5. Re-generate your initrd and update it in your boot bundle |
| |
| Encrypted datasets have keys loaded automatically or prompted for. |
| |
| If the root dataset contains children with `mountpoint=`s of `/etc`, `/bin`, `/lib*`, or `/usr`, they're mounted too. |
| |
| For complete documentation, see `dracut.zfs(7)`. |
| |
| ## cmdline |
| 1. `root=` | Root dataset is… | |
| ---------------------------|----------------------------------------------------------| |
| *(empty)* | the first `bootfs=` after `zpool import -aN` | |
| `zfs:AUTO`, `zfs:`, `zfs` | *(as above, but overriding other autoselection methods)* | |
| `ZFS=pool/dataset` | `pool/dataset` | |
| `zfs:pool/dataset` | *(as above)* | |
| |
| All `+`es are replaced with spaces (i.e. to boot from `root pool/data set`, pass `root=zfs:root+pool/data+set`). |
| |
| The dataset can be at any depth, including being the pool's root dataset (i.e. `root=zfs:pool`). |
| |
| `rootfstype=zfs` is equivalent to `root=zfs:AUTO`, `rootfstype=zfs root=pool/dataset` is equivalent to `root=zfs:pool/dataset`. |
| |
| 2. `spl_hostid`: passed to `zgenhostid -f`, useful to override the `/etc/hostid` file baked into the initrd. |
| |
| 3. `bootfs.snapshot`, `bootfs.snapshot=snapshot-name`: enables `zfs-snapshot-bootfs.service`, |
| which creates a snapshot `$root_dataset@$(uname -r)` (or, in the second form, `$root_dataset@snapshot-name`) |
| after pool import but before the rootfs is mounted. |
| Failure to create the snapshot is noted, but booting continues. |
| |
| 4. `bootfs.rollback`, `bootfs.rollback=snapshot-name`: enables `zfs-snapshot-bootfs.service`, |
| which `-Rf` rolls back to `$root_dataset@$(uname -r)` (or, in the second form, `$root_dataset@snapshot-name`) |
| after pool import but before the rootfs is mounted. |
| Failure to roll back will fall down to the rescue shell. |
| This has obvious potential for data loss: make sure your persistent data is not below the rootfs and you don't care about any intermediate snapshots. |
| |
| 5. If both `bootfs.snapshot` and `bootfs.rollback` are set, `bootfs.rollback` is ordered *after* `bootfs.snapshot`. |
| |
| 6. `zfs_force`, `zfs.force`, `zfsforce`: add `-f` to all `zpool import` invocations. |
| May be useful. Use with caution. |