Re: [PATCH many v5 0/7] add option to prevent suggesting previously used VMIDs

[Fiona Ebner <f.ebner@proxmox.com>]

Am 23.09.26 um 4:10 PM schrieb Michael Köppl:
> On Tue Sep 22, 2026 at 5:02 PM CEST, Fiona Ebner wrote:
> 
> [snip]
> 
>> 2. Recording every second ID can lead to a file larger than the 1 MiB
>> pmxcfs limit and then every operation will fail regardless of whether
>> the feature is turned on or not.
>>
>> 3. Remote migration uses destroy_{lxc_container,vm} directly if the
>> 'delete' parameter is set.
>>
>> For the second point, an example is:
>> [I] root@pve9a1 ~# expr $(seq 100 2 1000000 | wc --bytes) / 1024 / 1024
>> 3
>> This is unlikely to happen with regular operation of course, because we
>> always suggest the lowest free one, but it can't be ruled out. Not
>> entirely sure what to do about it, but it would be good if we can avoid
>> the issue. Maybe start dropping gaps and merging anyways if we get close
>> to the limit? At the very least, we might consider making the failure
>> non-critical if the feature is turned off.
> 
> Pondered a bit on this and my suggested approach would be to have 2
> thresholds at 512KiB and 768KiB, where write_id_list would warn for the
> "soft" threshold and start closing gaps at the "hard" threshold? That
> would give users fair warning to follow the suggested unique guest IDs
> and would potentially resolve the problem over time if ranges are
> merged as a result of it. What do you think?
> 
> I'd make it non-critical if 'unique' is turned off in any case.

Sounds good to me :)