Windows Server 2025 best practice - Async IO?

[Cha0s01]

I found the Windows Server 2025 best practice guide and it definitely helped. One thing it does not cover though is the "Async IO". Which is the best Async IO to choose for Windows Server 2025? My storage is a QNAP NAS with a 10GB connection.

Current settings in my home lab:
- Graphic card: Default
- Machine: q35
- BIOS: SeaBIOS (Lost data with UEFI on an unexpected NAS reboot)
- SCSI Controller: VirtIO SCSI single
- Qemu Agent: Checked
- TPM: v2
- Bus/Device: SCSI
- Cache: Write back
- IO thread: Checked
- Async IO: Default (io_uring)
- CPU Type: host

 

[Domino]

Stick to the default 'io_uring', it is non-blocking these days and is optimal for virtio-scsi-single, in some heavy load cases (overprovisioned), native can help somewhat, otherwise io_uring is your best option.

Also I tend to change the cache to Direct-Sync for boot-disks for peace of mind, the load on bootdisks tends to be very little after bootup so not really an issue setting to Direct-Sync. But do create additional drives for data which you can leave at default cache settings etc.

 

[Cha0s01]

Thank you @Domino. Ok, that sounds good. Valid point on the non-blocking. I did experiment with, Cache: Direct sync / Async IO: native right after I posted this and saw similar results. I did also notice that I think my QNAP is caching some data, the initial boot was slow, but the other boots were all 12 - 14 seconds.