Document how to restore GCP filestores from backups

docs/howto/filesystem-backups/restore-filesystem.md

@@ -0,0 +1,23 @@
+(howto:filesystem-backup:restore)=
+# Restore a Filesystem from a Backup
+
+In the event of a disaster and the filesystem needs recovering, this document
+covers those steps for the cloud providers.
+
+(howto:filesystem-backup:restore:gcp)=
+## GCP
+
+```{note}
+We follow GCP's guidance for [restoring fileshares from a backup](https://cloud.google.com/filestore/docs/backup-restore#restore)
+```
+
+To restore a share on a Filestore instance on GCP, we follow the documentation
+linked above. In short, this involves:
+
+1. [Go to the Filestore insances page](https://console.cloud.google.com/filestore/instances) in the GCP console
+1. Click the instance ID of the Filestore you want to restore and click the "Backups" tab
+1. Locate the backup you want to restore from (most likely the most recently created), and click (...) "More actions"
+1. Click "Restore backup" and then select "Source instance
+1. Click "Restore" and complete the dialog box that appears
+
+This should successfully restore the Filestore instance to its last backed-up state