diff --git a/@xen-orchestra/backups/_cleanVm.js b/@xen-orchestra/backups/_cleanVm.js
index 6afbfdd082b..e27468af226 100644
--- a/@xen-orchestra/backups/_cleanVm.js
+++ b/@xen-orchestra/backups/_cleanVm.js
@@ -119,7 +119,7 @@ const listVhds = async (handler, vmDir) => {
           const list = await handler.list(vdiDir, {
             filter: file => isVhdFile(file) || INTERRUPTED_VHDS_REG.test(file),
           })
-          aliases[vdiDir] = list.filter(vhd => isVhdAlias(vhd))
+          aliases[vdiDir] = list.filter(vhd => isVhdAlias(vhd)).map(file => `${vdiDir}/${file}`)
           list.forEach(file => {
             const res = INTERRUPTED_VHDS_REG.exec(file)
             if (res === null) {
@@ -249,15 +249,11 @@ exports.cleanVm = async function cleanVm(
     }
   }
 
-  // 2022-01-17 - FBP & JFT - Temporary disable aliases checking as it appears problematic
-  //
   // check if alias are correct
   // check if all vhd in data subfolder have a corresponding alias
-  // await asyncMap(Object.keys(aliases), async dir => {
-  //   await checkAliases(aliases[dir], `${dir}/data`, { handler, onLog, remove })
-  // })
-  // Avoid a ESLint unused variable
-  noop(aliases)
+  await asyncMap(Object.keys(aliases), async dir => {
+    await checkAliases(aliases[dir], `${dir}/data`, { handler, onLog, remove })
+  })
 
   // remove VHDs with missing ancestors
   {
diff --git a/@xen-orchestra/backups/writers/_MixinBackupWriter.js b/@xen-orchestra/backups/writers/_MixinBackupWriter.js
index 62d3cb72ec8..5fc18516e85 100644
--- a/@xen-orchestra/backups/writers/_MixinBackupWriter.js
+++ b/@xen-orchestra/backups/writers/_MixinBackupWriter.js
@@ -44,13 +44,14 @@ exports.MixinBackupWriter = (BaseClass = Object) =>
 
     async afterBackup() {
       const { disableMergeWorker } = this._backup.config
+      // merge worker only compatible with local remotes
+      const { handler } = this._adapter
+      const willMergeInWorker = !disableMergeWorker && typeof handler._getRealPath === 'function'
 
-      const { merge } = await this._cleanVm({ remove: true, merge: disableMergeWorker })
+      const { merge } = await this._cleanVm({ remove: true, merge: !willMergeInWorker })
       await this.#lock.dispose()
 
-      // merge worker only compatible with local remotes
-      const { handler } = this._adapter
-      if (merge && !disableMergeWorker && typeof handler._getRealPath === 'function') {
+      if (merge && willMergeInWorker) {
         const taskFile =
           join(MergeWorker.CLEAN_VM_QUEUE, formatFilenameDate(new Date())) +
           '-' +
diff --git a/@xen-orchestra/fs/src/s3.js b/@xen-orchestra/fs/src/s3.js
index ea1b70f0342..d8d584b194e 100644
--- a/@xen-orchestra/fs/src/s3.js
+++ b/@xen-orchestra/fs/src/s3.js
@@ -19,8 +19,25 @@ const MAX_OBJECT_SIZE = 1024 * 1024 * 1024 * 1024 * 5 // 5TB
 const IDEAL_FRAGMENT_SIZE = Math.ceil(MAX_OBJECT_SIZE / MAX_PARTS_COUNT) // the smallest fragment size that still allows a 5TB upload in 10000 fragments, about 524MB
 
 const { warn } = createLogger('xo:fs:s3')
-
+  // some objectstorage provider like backblaze, can answer a 500/503 routinely
+  // in this case we should retry,  and let their load balancing do its magic
+  // https://www.backblaze.com/b2/docs/calling.html#error_handling
+  const retryOptions = {
+    delays: [100, 200, 500, 1000, 2000],
+    when: e => e.code === 'InternalError',
+    onRetry(error) {
+      warn('retrying writing file', {
+        attemptNumber: this.attemptNumber,
+        delay: this.delay,
+        error,
+        file: this.arguments[0],
+      })
+    },
+  }
 export default class S3Handler extends RemoteHandlerAbstract {
+
+
+
   constructor(remote, _opts) {
     super(remote)
     const { allowUnauthorized, host, path, username, password, protocol, region } = parse(remote.url)
@@ -123,21 +140,7 @@ export default class S3Handler extends RemoteHandlerAbstract {
     }
   }
 
-  // some objectstorage provider like backblaze, can answer a 500/503 routinely
-  // in this case we should retry,  and let their load balancing do its magic
-  // https://www.backblaze.com/b2/docs/calling.html#error_handling
-  @decorateWith(pRetry.wrap, {
-    delays: [100, 200, 500, 1000, 2000],
-    when: e => e.code === 'InternalError',
-    onRetry(error) {
-      warn('retrying writing file', {
-        attemptNumber: this.attemptNumber,
-        delay: this.delay,
-        error,
-        file: this.arguments[0],
-      })
-    },
-  })
+  @decorateWith(pRetry.wrap, retryOptions)
   async _writeFile(file, data, options) {
     return this._s3.putObject({ ...this._createParams(file), Body: data })
   }
diff --git a/packages/vhd-lib/index.js b/packages/vhd-lib/index.js
index 65b0376c551..e659e8863af 100644
--- a/packages/vhd-lib/index.js
+++ b/packages/vhd-lib/index.js
@@ -1,3 +1,4 @@
+
 exports.chainVhd = require('./chain')
 exports.checkFooter = require('./checkFooter')
 exports.checkVhdChain = require('./checkChain')
@@ -12,3 +13,6 @@ exports.VhdDirectory = require('./Vhd/VhdDirectory').VhdDirectory
 exports.VhdFile = require('./Vhd/VhdFile').VhdFile
 exports.VhdSynthetic = require('./Vhd/VhdSynthetic').VhdSynthetic
 exports.Constants = require('./_constants')
+const {isVhdAlias, resolveAlias} = require('./_resolveAlias')
+exports.isVhdAlias = isVhdAlias
+exports.resolveAlias = resolveAlias