[pve-devel] [PATCH v3 manager 1/2] HDEdit: check iothread by default and move it from advanced section

[Matthias Heiserer]

On 20.05.2022 08:52, Fabian Ebner wrote:
> Am 19.05.22 um 15:35 schrieb Matthias Heiserer:
>> On 18.05.2022 11:40, Fabian Ebner wrote:
>>> Am 12.05.22 um 11:24 schrieb Matthias Heiserer:
>>>> Existing disks are not changed by this.
>>>> Especially in benchmarks, iothreads significantly improve IO
>>>> performance.
>>>>
>>>>
>>>> Signed-off-by: Matthias Heiserer <m.heiserer at proxmox.com>
>>>> ---
>>>>
>>>> Changes from v2:
>>>> * also check iothread when adding a disk to an existing VM and
>>>>    scsi single
>>>> * use bind instead of hardcoded true
>>>
>>> This feels like to much automagic to me, because changes to the checkbox
>>> (even if checkbox is for a virtio disk) will change the controller type
>>> and vice versa. This also makes it impossible to only set iothread on
>>> certain disks or use the "Virtio SCSI single" controller type without
>>> setting iothread.
>>>
>>> Is it possible to instead have the checkbox be invalid with an
>>> appropriate error for the user when it's a bad configuration?
>>
>> Changes to the checkbox already change the Controller to Virtio SCSI
>> (single), regardless of what was selected before. Anyways, the automatic
>> change only happens in the wizard.
>>
> 
> You're right, and I'd argue that the current behavior isn't ideal either
> ;). I guess with only a single scsi disk it makes sense to automatically
> switch, because the iothread setting would be invalid otherwise. It also
> happens for a virtio disk though, where the scsi controller type isn't
> even visible in the disk edit tab. One can still argue that it's just
> not relevant there. But we switched to using a multi-disk panel some
> time ago, and in that context it's just confusing, because changes to
> each iothread checkbox will affect the scsi controller type.
> 
I send in a v4, please take a look.
There is still no warning for bad configurations, rather, I removed the 
bin. Now, you can configure all disks individually, with SCSI single and 
iothread enabled still being the default. The iothread are still binded 
to the scsi controller, so if someone were to change some iothread 
settings, go back to the controller, set it to something other than SCSI 
single, then change it back to scsi single, the iothread configuration 
would be lost/all enabled.

Please let me know what you think about it, if it's closer to what you 
have in mind.