diff --git a/@xen-orchestra/backups/_cleanVm.js b/@xen-orchestra/backups/_cleanVm.js
index af626a44e..aaa3d2932 100644
--- a/@xen-orchestra/backups/_cleanVm.js
+++ b/@xen-orchestra/backups/_cleanVm.js
@@ -124,6 +124,8 @@ exports.cleanVm = async function cleanVm(
   vmDir,
   { fixMetadata, remove, merge, mergeLimiter = defaultMergeLimiter, onLog = noop }
 ) {
+  const limitedMergeVhdChain = mergeLimiter(mergeVhdChain)
+
   const handler = this._handler
 
   const vhds = new Set()
@@ -344,7 +346,7 @@ exports.cleanVm = async function cleanVm(
 
   const doMerge = () => {
     const promise = asyncMap(toMerge, async chain => {
-      mergeVhdChain(chain, { handler, onLog, remove, merge })
+      limitedMergeVhdChain(chain, { handler, onLog, remove, merge })
     })
     return merge ? promise.then(sizes => ({ size: sum(sizes) })) : promise
   }