diff --git a/systems/x86_64-linux/sgx/firefly.nix b/systems/x86_64-linux/sgx/firefly.nix
index 9eb7000..7b03607 100644
--- a/systems/x86_64-linux/sgx/firefly.nix
+++ b/systems/x86_64-linux/sgx/firefly.nix
@@ -53,6 +53,12 @@ in
       "d ${inbox} 0700 firefly-iii-data-importer nginx -"
       "d ${importerHome}/.aqbanking/imexporters/csv/profiles 0700 firefly-iii-data-importer nginx -"
       "L+ ${importerHome}/.aqbanking/imexporters/csv/profiles/firefly.conf - - - - ${fireflyCsvProfile}"
+      # Disable btrfs CoW on Firefly's SQLite directory — random-write
+      # SQLite traffic fragments CoW filesystems quickly. New files in
+      # this dir inherit the +C attribute. Existing database.sqlite,
+      # -wal, -shm need a one-time recreate to apply (use sqlite3 .backup
+      # into a fresh +C file). No-op on non-btrfs filesystems.
+      "h /var/lib/firefly-iii/storage/database - - - - +C"
     ];
 
     services.firefly-sparda-fetch = {