add btrbk configs

pc_fedora.md

@@ -18,6 +18,115 @@ protect.
 9. On the faster 1TB drive create an unencrypted btrfs partition and mount it at "/steam"
 10. Click "Done" and begin installation
 
+## btrbk
+
+```bash
+sudo dnf install btrbk
+```
+
+As usual, you'll need a snapshot service and backup service. These get more complicated
+with multi-drive mounts (but actually easier at the same time since each volume is self-
+contained).
+
+/etc/btrbk/btrbk_snapshots.conf
+
+```conf
+snapshot_preserve_min   24h
+snapshot_preserve       24h 14d
+
+volume /mnt/btr_pools
+    subvolume           root
+    snapshot_dir        root/.snapshots
+
+volume /mnt/btr_pools
+    subvolume           home
+    snapshot_dir        home/.snapshots
+
+volume /mnt/btr_pools
+    subvolume           steam
+    snapshot_dir        steam/.snapshots
+```
+
+/etc/btrbk/btrbk_backup.conf
+
+```conf
+snapshot_preserve_min   all
+snapshot_create         no
+target_preserve_min     no
+target_preserve         24h 7d 4w *m
+
+volume /mnt/btr_pools
+    subvolume           root
+    snapshot_dir        root/.snapshots
+    target              /mnt/backup/root
+
+volume /mnt/btr_pools
+    subvolume           home
+    snapshot_dir        home/.snapshots
+    target              /mnt/backup/home
+
+volume /mnt/btr_pools
+    subvolume           steam
+    snapshot_dir        steam/.snapshots
+    target              /mnt/backup/steam
+```
+
+Then you'll need a service to run btrbk_snapshots and btrbk_backup.
+
+/etc/systemd/system/btrbk_snapshots.service
+
+```conf
+[Unit]
+Description=Runs btrbk with config file at /etc/btrbk/btrbk_snapshots.conf
+
+[Service]
+ExecStart=/usr/bin/btrbk -c /etc/btrbk/btrbk_snapshots.conf -v run
+```
+
+/etc/systemd/system/btrbk_backup.service
+
+```conf
+[Unit]
+Description=Runs btrbk with config file at /etc/btrbk/btrbk_backup.conf
+
+[Service]
+ExecStart=/usr/bin/btrbk -c /etc/btrbk/btrbk_backup.conf -v run
+```
+
+And timers to run the btrbk services on a regular schedule.
+
+/etc/systemd/system/btrbk_snapshots.timer
+
+```conf
+[Unit]
+Description=Run btrbk_snapshots every hour
+
+[Timer]
+OnCalendar=hourly
+AccuracySec=10min
+Persistent=true
+Unit=btrbk_snapshots.service
+
+[Install]
+WantedBy=timers.target
+```
+
+/etc/systemd/system/btrbk_backup.timer
+
+```conf
+[Unit]
+Description=Run btrbk_backup every hour
+
+[Timer]
+OnCalendar=hourly
+AccuracySec=10min
+Persistent=true
+Unit=btrbk_backup.service
+
+[Install]
+WantedBy=timers.target
+```
+
 ## RDP with autologin
 
 https://askubuntu.com/questions/1396745/21-10-make-screen-share-password-permanent