the last rewrite of the stream processing ( spring 2025 ) focused on stability and memory footprint, and , on a standard cpu, it tops at around 300MB/s per backup job. Your benchmarks are very interesting, and they confirm most of it.
this limit was not really an issue since, in most case the xapi was limiting around 100MB/s per disk , but it will be more a more visible limit
Note that master have some fixes on the memory usage (not related to backups)
That's why we have started an internal workforce focused on performance, with all the teams from the kernel to the backups, including storage, network and xapi.
If I can brag a little :
[image: 1779106650898-afd7b59b-a4f0-4a92-88ee-2c7ba52d18bf-image.jpeg]
i9 , nvme disk , backup to a nvme disk in passthrough, xoa and vm are on the same host, so it's quite far from real world data, but it shows where the limit is
