HI there.. welcome to the forums...
That log entry isn't tied to the proxy VM's SCSI controller type, which is why switching to PVSCSI didn't change anything.
Based on the VMware/Broadcom VDDK documentation, asynchronous I/O support is associated with the NBD/NBDSSL transport modes rather than HotAdd transport. Since your job is running in transport mode: [hotadd], seeing async I/O: [unsupported] appears to be expected behavior and not an indication of a failure.
If backups are completing normally and performance is acceptable, this alone usually is not something to worry about. If you're troubleshooting an actual performance issue, then opening a support case would make sense so the data mover logs can be reviewed in detail.
That log entry isn't tied to the proxy VM's SCSI controller type, which is why switching to PVSCSI didn't change anything.
Based on the VMware/Broadcom VDDK documentation, asynchronous I/O support is associated with the NBD/NBDSSL transport modes rather than HotAdd transport. Since your job is running in transport mode: [hotadd], seeing async I/O: [unsupported] appears to be expected behavior and not an indication of a failure.
If backups are completing normally and performance is acceptable, this alone usually is not something to worry about. If you're troubleshooting an actual performance issue, then opening a support case would make sense so the data mover logs can be reviewed in detail.
Statistics: Posted by Sturniolo — May 20, 2026 6:51 pm
