diff --git a/coreos-config/templates/backup.sh.j2 b/coreos-config/templates/backup.sh.j2
index ce22ccc..c5c2766 100755
--- a/coreos-config/templates/backup.sh.j2
+++ b/coreos-config/templates/backup.sh.j2
@@ -44,7 +44,7 @@ info "Pruning repository"
 
 borg prune                          \
     --list                          \
-    --prefix '{hostname}-'          \
+    --glob-archives '{hostname}-*'  \
     --show-rc                       \
     --keep-daily    7               \
     --keep-weekly   4               \