Please clarify - Windows disk controller

[tiberius]

Dear all,

Please clarify which disk controller is recommended for Windows guests If performance is a goal.
I do ask because based on the Wiki it seems to be virtio / virtio-bulk but the help text tends to use scsi which is also kinda virtio new school + the video howto also uses the scsi disk controller !?

Bonus question: What is the difference between write back and write back unsafe ?

I would appreciate a profound feedback.

Cheers

 

[tiberius]

BUMp

 

[t.lamprecht]

Hi,

Please clarify which disk controller is recommended for Windows guests If performance is a goal.
I do ask because based on the Wiki it seems to be virtio / virtio-bulk but the help text tends to use scsi which is also kinda virtio new school + the video howto also uses the scsi disk controller !?

see: https://pve.proxmox.com/pve-docs/chapter-qm.html#qm_hard_disk

Bonus question: What is the difference between write back and write back unsafe ?

See: https://pve.proxmox.com/wiki/Performance_Tweaks#Small_Overview "writeback" is "writeback" and "writeback (unsafe)" maps to "unsafe" in the table.

 

[tiberius]

see: https://pve.proxmox.com/pve-docs/chapter-qm.html#qm_hard_disk

Thanks but as I mentioned in my post I am confused because the wiki for eg. windows 10 recommends virtio and not scsi:
https://pve.proxmox.com/wiki/Windows_10_guest_best_practices

So virtio or scsi is recommended for windows guests and if someone have extra time WHY (sry. I simply want to understand) ?

See: https://pve.proxmox.com/wiki/Performance_Tweaks#Small_Overview "writeback" is "writeback" and "writeback (unsafe)" maps to "unsafe" in the table.

Cheers this solved my question!

 

[udo]

So virtio or scsi is recommended for windows guests and if someone have extra time WHY (sry. I simply want to understand) ?

Hi,
virtio is an good choice but has some limits - so you can't use TRIM with virtio.

This is one reason why scsi with an Virtio Scsi-driver (single disks for additional IO-Thread) is the new favorit.
With this setting you get performance and you can use TRIM, which is not for SSDs usefull only.
Also with ceph you want TRIM to delete unused space...

Udo