diff --git a/hosts/mastodon/default.nix b/hosts/mastodon/default.nix
index a48183b8..9790d7f5 100644
--- a/hosts/mastodon/default.nix
+++ b/hosts/mastodon/default.nix
@@ -10,7 +10,10 @@
   networking.hostName = "mastodon";
 
   services = {
-    backup.paths = [ "/var/lib/mastodon/" ];
+    backup = {
+      exclude = [ "/var/lib/mastodon/public-system/cache/" ];
+      paths = [ "/var/lib/mastodon/" ];
+    };
 
     # Sidekiq monitoring
     collectd.plugins = {