Win11 Disk Performance Problems | VirtIO SCSI + Discard + IO Thread

[Jns62Xya]

Hi!

i have some performance problems with a (the only one) windows 11 vm on my Proxmox VE! Totaly slow disk reads. Starting Programs is to slow for the underlaying hardware (my feeling...) I've tried cache=writeback, ssd=0/1 etc...

Host:
- Dell R620 with PERC HW RAID (8x 1TB 7,2K SAS) as RAID 10.
- Proxmox VE 9.2.3 with local-lvm storage

VM:
- Windows 11 Pro
- 16Gb RAM (no balooning!)
- CPU 2 Sockets, 4 Cores (x86-64-v2-AES)
- VirtIO SCSI disk with no cache, discard, IO thread
- Redhat VirtIO Driver installed on Windows 11

Tests with CrystalDiskMark:
Random Read: 1.08MB/s
Random Write: 9.11MB/s

Where is my bottleneck?

 

[tomellm]

Was not choosing "Write Back" for the virtual hard disk cache a conscious decision?

In any case, I imagine you have seen this page on best practices?