feat: enable zram

modules/nixos/base/misc.nix

@@ -27,6 +27,22 @@
   # https://nixos.org/manual/nix/stable/command-ref/conf-file.html#conf-auto-optimise-store
   nix.settings.auto-optimise-store = true;
 
+  # Enable in-memory compressed devices and swap space provided by the zram kernel module.
+  # By enable this, we can store more data in memory instead of fallback to disk-based swap devices directly, and thus improve I/O performance.
+  zramSwap = {
+    enable = true;
+    # one of "lzo", "lz4", "zstd"
+    algorithm = "zstd";
+    # Priority of the zram swap devices. 
+    # It should be a number higher than the priority of your disk-based swap devices
+    # (so that the system will fill the zram swap devices before falling back to disk swap).
+    priority = 5;
+    # Maximum total amount of memory that can be stored in the zram swap devices (as a percentage of your total memory). 
+    # Defaults to 1/2 of your total RAM. Run zramctl to check how good memory is compressed. 
+    # This doesn’t define how much memory will be used by the zram swap devices.
+    memoryPercent = 50;
+  };
+
   # for power management
   services = {
     power-profiles-daemon = {