diff --git a/servers/mimir/default.nix b/servers/mimir/default.nix
index 5ac606a..477aa69 100644
--- a/servers/mimir/default.nix
+++ b/servers/mimir/default.nix
@@ -38,27 +38,6 @@ in
     efiInstallAsRemovable = true;
   };
 
-  environment.persistence."/persist" = {
-    enable = true;
-    hideMounts = true;
-
-    directories = [
-      "/var/backup"
-      "/var/log"
-      "/var/lib"
-
-      "/home"
-    ];
-
-    files = [
-      "/etc/machine-id"
-      "/etc/ssh/ssh_host_ed25519_key"
-      "/etc/ssh/ssh_host_ed25519_key.pub"
-      "/etc/ssh/ssh_host_rsa_key"
-      "/etc/ssh/ssh_host_rsa_key.pub"
-    ];
-  };
-
   networking.firewall.allowedTCPPorts = [ 2222 ];
 
   services.beszel.agent.environment = {
diff --git a/servers/mimir/disks.nix b/servers/mimir/disks.nix
index 1756a25..7be572e 100644
--- a/servers/mimir/disks.nix
+++ b/servers/mimir/disks.nix
@@ -70,4 +70,62 @@
   };
 
   fileSystems."/persist".neededForBoot = true;
+
+  boot.initrd.postResumeCommands =
+    let
+      rootVolume = "@root";
+    in
+    lib.mkAfter ''
+      mkdir /btrfs_tmp
+      mount /dev/sda3 /btrfs_tmp
+      if [[ -e /btrfs_tmp/${rootVolume} ]]; then
+          mkdir -p /btrfs_tmp/old_roots
+          timestamp=$(date --date="@$(stat -c %Y /btrfs_tmp/${rootVolume})" "+%Y-%m-%-d_%H:%M:%S")
+          mv /btrfs_tmp/${rootVolume} "/btrfs_tmp/old_roots/$timestamp"
+      fi
+
+      delete_subvolume_recursively() {
+          IFS=$'\n'
+          for i in $(btrfs subvolume list -o "$1" | cut -f 9- -d ' '); do
+              delete_subvolume_recursively "/btrfs_tmp/$i"
+          done
+          btrfs subvolume delete "$1"
+      }
+
+      for i in $(find /btrfs_tmp/old_roots/ -maxdepth 1 -mtime +30); do
+          delete_subvolume_recursively "$i"
+      done
+
+      btrfs subvolume create /btrfs_tmp/${rootVolume}
+      umount /btrfs_tmp
+    '';
+
+  environment.persistence."/persist" = {
+    enable = true;
+    hideMounts = true;
+
+    directories = [
+      "/var/backup"
+      "/var/log"
+      "/var/lib"
+
+      "/home"
+    ];
+
+    files = [
+      "/etc/machine-id"
+    ];
+  };
+
+  services.openssh.hostKeys = [
+    {
+      bits = 4096;
+      path = "/persist/etc/ssh/ssh_host_rsa_key";
+      type = "rsa";
+    }
+    {
+      path = "/persist/etc/ssh/ssh_host_ed25519_key";
+      type = "ed25519";
+    }
+  ];
 }