add btrfs-raid1 example

example/btrfs-raid1.nix

@@ -0,0 +1,65 @@
+{
+  disko.devices = {
+    disk = {
+      nvme0 = {
+        type = "disk";
+        device = "/dev/nvme0n1";
+        content = {
+          type = "gpt";
+          partitions = {
+            ESP = {
+              type = "EF00";
+              size = "1024M";
+              name = "boot";
+              content = {
+                type = "filesystem";
+                format = "vfat";
+                mountpoint = "/boot";
+                mountOptions = [
+                  "umask=0022"
+                  "iocharset=utf8"
+                  "rw"
+                ];
+              };
+            };
+            empty = {
+              # in order for btrfs raid to work we need to do this
+              size = "100%";
+            };
+          };
+        };
+      };
+      nvme1 = {
+        type = "disk";
+        device = "/dev/nvme1n1";
+        content = {
+          type = "gpt";
+          partitions = {
+            root = {
+              size = "100%";
+              content = {
+                type = "btrfs";
+                extraArgs = [
+                  "-f"
+                  "-m raid1"
+                  "-d single"
+                  "/dev/nvme0n1p2" # needs to be partition 2 of 1st disk and needs to be 2nd disk
+                ];
+                mountpoint = "/";
+                mountOptions = [
+                  "rw"
+                  "ssd_spread"
+                  "max_inline=256"
+                  "commit=150"
+                  "compress=zstd"
+                  "noatime"
+                  "discard=async"
+                ];
+              };
+            };
+          };
+        };
+      };
+    };
+  };
+}