add section about backups and subvolumes

infrastructure/graduated/arch/README.md

@@ -577,8 +577,8 @@ Before you begin, go through the usual process of setting up an encrypted drive.
 you're using Gnome I recommend using the GUI since it handles encrypted USB drives
 really nicely.
 
-The only thing I'd recommend doing manually is creating the mountpoint as a read-only
+First, I'd recommend manually creating the mountpoint and setting it as a read-only.
-subvolume. This prevents backups from being written to the root device when the backup
+This prevents backups from being written to the root device when the backup
 disk isn't mounted.
 
 ```bash
@@ -586,6 +586,14 @@ btrfs sub create /btr_pools/backup
 btrfs property set /btr_pools/backup ro true
 ```
 
+Second, I'd recommend creating subvolumes within your existing volumes for things you
+don't want backed up. These include:
+
+1. /var/lib/libvirt
+2. Nextcloud
+
+Now set up the backup:
+
 1. Create a backup config
 
     /etc/btrbk/backups.conf
@@ -932,9 +940,9 @@ Choose noto-fonts
 #### Gnome Extensions
 
 1. AlphabeticalAppGrid@stuarthayhurst
-2. Vitals@CoreCoding.com
+2. <Vitals@CoreCoding.com>
-3. dash-to-dock@micxgx.gmail.com
+3. <dash-to-dock@micxgx.gmail.com>
-4. tactile@lundal.io
+4. <tactile@lundal.io>
 
 ### Avahi (Bonjour)