zfs: zfs_txg_timeout 30 -> 120

modules/zfs.nix

@@ -34,7 +34,7 @@ in
     in
     [
       "zfs.zfs_arc_max=${builtins.toString b}"
-      "zfs.zfs_txg_timeout=30" # longer TXG open time = larger sequential writes = better HDD throughput
+      "zfs.zfs_txg_timeout=120" # longer TXG open time = larger sequential writes
       "zfs.zfs_dirty_data_max=8589934592" # 8GB dirty data buffer (default 4GB) for USB HDD write smoothing
       "zfs.zfs_delay_min_dirty_percent=80" # delay write throttling until 80% dirty (default 60%)
       "zfs.zfs_vdev_async_write_max_active=30" # more concurrent async writes to vdevs (default 10)

services/postgresql.nix

@@ -19,6 +19,14 @@
     enable = true;
     package = pkgs.postgresql_16;
     dataDir = service_configs.postgres.dataDir;
+    settings = {
+      # ZFS provides checksumming and atomic writes, making PostgreSQL's
+      # full_page_writes redundant. Disabling reduces write amplification
+      # and SSD wear on the zpool.
+      # Did this in conjunction with setting recordsize=8k
+      # on the zvolume this is on
+      full_page_writes = false;
+    };
   };
 
 }