Q: various VirtIO SCSI Config scenarios > BSOD vs Not for Win10 guest

[fortechitsolutions]

Hi, I have a client asking me for clarification on this topic, and I am not quite sure.

Best practice guide in proxmox docs
https://pve.proxmox.com/wiki/Windows_10_guest_best_practices

suggests we should use ""SCSI" as bus with "VirtIO SCSI" as controller."

My normal routine in past was to use

scsi controller = Virtio SCSI; and then
HDD = virtio (ie, virtio0 attached to above controller)

which is slightly different. I think.

My client had setup a VM with settings,
scsi controller = VIrtioSCSI; andthen
HDD = SCSI

and this seemed to work well. He then tried to flip it from SCSI>Virtio and gets BSOD when the win10pro VM boots. So reverted back.
he is using virtio-win-0.1.190 as ISO / driver source for virtio driver
he also has other misc drivers installed from this ISO (ie, guest addon, balloon driver, etc)

so I guess question is 2-fold, sort of,

- does it really matter to follow the wiki best practices where you set SCSI bus or is Virtio as bus OK / same / no difference in performance?
and
- is there an easy-obvious reason why he would get BSOD when trying to move from one controller config to other / as described here?

I just was not terribly sure so thought I would ask for any feedback.

many thanks!

Tim

 

[Ramalama]

If your windows misses the driver, because you didn't installed it like in best practices, no one is going to change best practices now

Any method works, im using here always the "Virtio Block".
Virtio Block provides usually anyway more speed as scsi.
However, to get rid of your bsod, add an additional empty drive as virtio block, install the driver and then you can change and you won't get bsod....

 

[fortechitsolutions]

Hi, I believe that attaching an empty drive (not changing boot drive) causes the BSOD. I will double check with client.

I agree that that is cleanest way to get the virtio driver integrated. In theory the virtio driver is already present and working / as per my description,

I also agree, my preference is virtio block, not scsi. hence my confusion that the 'best practice' appears to suggest something that is not optimal.
(ie, did you go and read https://pve.proxmox.com/wiki/Windows_10_guest_best_practices ? prior to making your post back to me on this thread?)

Tim

 

[Ramalama]

Yeah, i read that once and forgot it, sry.
As far i remember, you should select scsi instead of virtio block, because the scsi commands can passthrough to disks directly or something like that.

Probably for some more enterprise gear (real scsi drives) etc... It's more beneficial or faster. But from my own testings a simple virtio block always outperfoms the scsi bus, especially in the writing performance.

However, the autor that wrote that guide is probably more experienced as we both are, performance must not be everything, or the guide is outdated and virtio block didn't existed that time or whatever, im not going to break my head about that.

However, my main concern to you is more about the bsod. That's comming definitively from the drivers.

Cheers

 

[fortechitsolutions]

sounds good - thanks for the added detail!
I agree, the BSOD is bad / should be resolved. I'll look at this with my client and figure out what is going on.

generally speaking, I agree with you - I have found that VirtIO 'just works' and generally performs 'very well'. (ie, no scsi mentioned anywhere normally in my stock drive setup / just virtio).

Once I get some progress I will followup back to the thread.

Thanks,

Tim