diff --git a/hosts/caveman/default.nix b/hosts/caveman/default.nix
index ab23d49f..ce9195b7 100644
--- a/hosts/caveman/default.nix
+++ b/hosts/caveman/default.nix
@@ -23,7 +23,8 @@
 
   services = {
     caveman = {
-      redis.maxmemory = config.microvm.mem * 1024 * 1024 / 2;
+      # leave 4 GB for caveman services
+      redis.maxmemory = (config.microvm.mem - 4) * 1024 * 1024;
 
       hunter = {
         enable = true;