diff --git a/src/main.rs b/src/main.rs
index a3c734c..5801b36 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -171,7 +171,10 @@ impl AppHandler {
 
     /// returns Memory per vCPU and Disk per vCPU ratio
     fn slot_ratios(&self) -> (usize, usize) {
-        let total_storage_mib = self.host_config.max_disk_reservation_mib as usize;
+        let total_storage_mib =
+            self.host_config
+                .max_disk_reservation_mib
+                .saturating_sub(self.host_resource.reserved_disk_mib) as usize;
         let available_cpus =
             self.host_config
                 .max_vcpu_reservation