fix(vhd-lib/createStreamNbd): create binary instead of object stream

This reduces memory consumption.

CHANGELOG.unreleased.md

@@ -17,6 +17,8 @@
 
 ### Bug fixes
 
+- [Backup] Reduce memory consumption when using NBD (PR [#7216](https://github.com/vatesfr/xen-orchestra/pull/7216))
+
 > Users must be able to say: “I had this issue, happy to know it's fixed”
 
 - [REST API] Returns a proper 404 _Not Found_ error when a job does not exist instead of _Internal Server Error_
@@ -41,6 +43,7 @@
 <!--packages-start-->
 
 - @xen-orchestra/xapi patch
+- vhd-lib patch
 - xo-server minor
 - xo-server-auth-saml minor
 - xo-server-transport-email major

packages/vhd-lib/createStreamNbd.js

@@ -14,8 +14,8 @@ const {
 const { fuHeader, checksumStruct } = require('./_structs')
 const assert = require('node:assert')
 
-exports.createNbdRawStream = async function createRawStream(nbdClient) {
-  const stream = Readable.from(nbdClient.readBlocks())
+exports.createNbdRawStream = function createRawStream(nbdClient) {
+  const stream = Readable.from(nbdClient.readBlocks(), { objectMode: false })
 
   stream.on('error', () => nbdClient.disconnect())
   stream.on('end', () => nbdClient.disconnect())
@@ -103,7 +103,7 @@ exports.createNbdVhdStream = async function createVhdStream(nbdClient, sourceStr
     yield bufFooter
   }
 
-  const stream = Readable.from(iterator())
+  const stream = Readable.from(iterator(), { objectMode: false })
   stream.length = (offsetSector + blockSizeInSectors + 1) /* end footer */ * SECTOR_SIZE
   stream._nbd = true
   stream.on('error', () => nbdClient.disconnect())