build02: add swap

build02/configuration.nix

@@ -3,6 +3,7 @@
 {
   imports = [
     ../roles/common.nix
+    ../roles/swap.nix
     ../roles/hardware/hetzner-amd.nix
     ../roles/hetzner-network.nix
     ../roles/hercules-ci

roles/swap.nix

@@ -0,0 +1,6 @@
+# https://github.com/zfsonlinux/pkg-zfs/wiki/HOWTO-use-a-zvol-as-a-swap-device
+# zfs create -V 16G -b $(getconf PAGESIZE) -o logbias=throughput -o sync=always -o primarycache=metadata -o com.sun:auto-snapshot=false /dev/zvol/zroot/swap
+# mkswap -f /dev/zvol/zroot/swap
+{
+  swapDevices = [{ device = "/dev/zvol/zroot/swap"; }];
+}