diff --git a/README.md b/README.md
index 8c9350d..48243d7 100644
--- a/README.md
+++ b/README.md
@@ -76,8 +76,15 @@ different services:
 - mempool: upgrade web, api and db in docker-compose.yaml.
 - LNbits: upgrade in docker-compose.yaml.
 
-### How to backup data
+## How to backup data
 
-TODO: explain how to back all the data up with a rsync.
+The relevant assets you should backup are:
+- Your `.env` file.
+- Your `docker-compose-yaml` (if you changed any of its contents).
+- Your data folder.
+
+An `rsync` to another server should do the trick. You probably don't want to
+copy the bitcoin blockchain and the electrs indexes due to their massive size.
+You can use the `--exclude` option when calling `rsync` to exclude them.