Re: [pve-devel] [PATCH pve-manager master v1 2/2] fix #6652: d/postinst: enable autoactivation for Ceph OSD LVs

["Fabian Grünbichler" <f.gruenbichler@proxmox.com>]

On August 13, 2025 11:40 am, Max R. Carrara wrote:
> On Wed Aug 13, 2025 at 11:02 AM CEST, Fabian Grünbichler wrote:
>> On August 13, 2025 10:50 am, Max R. Carrara wrote:
>> > On Wed Aug 13, 2025 at 9:52 AM CEST, Fabian Grünbichler wrote:
>> >> On August 12, 2025 6:46 pm, Max R. Carrara wrote:
>> >> > Introduce a new helper command pve-osd-lvm-enable-autoactivation,
>> >> > which gracefully tries to enable autoactivation for all logical
>> >> > volumes used by Ceph OSDs while also activating any LVs that aren't
>> >> > active yet. Afterwards, the helper attempts to bring all OSDs online.
>> >>
>> >> I think this is probably overkill - this only affects a specific non
>> >> standard setup, the breakage is really obvious, and the fix is easy:
>> >> either run lvchange on all those LVs, or recreate the OSDs after the fix
>> >> for creation is rolled out..
>> >>
>> >> i.e., the fallout from some edge cases not being handled correctly in
>> >> the 200 line helper script here is probably worse than the few setups
>> >> that run into the original issue that we can easily help along
>> >> manually..
>> > 
>> > I mean, this script doesn't really do much, and the LVs themselves are
>> > fetched via `ceph-volume` ... But then again, you're probably right that
>> > it might just break somebody else's arcane setup somewhere.
>> > 
>> > As an alternative, I wouldn't mind writing something for the release
>> > notes' known issues section (or some other place). Assuming a standard
>> > setup*, all that the user would have to do is identical to what the
>> > script does, so nothing too complicated.
>>
>> but the known issue will be gone, except for the handful of users that
>> ran into it before the fix was rolled out.. this is not something you
>> noticed 5 months later?
> 
> Are you sure, though? There might very well be setups out there that are
> only rebooted every couple months or so--not everybody is as diligent
> with their maintenance, unfortunately. We don't really know how common /
> rare it is to set up a DB / WAL disk for OSDs.

I am not opposed to adding it to the known issues, I just think it's not
a very common issue to run into in the first place.

>> > (*OSDs with WAL + DB on disks / partitions without anything else inbetween)
>>
>> I am not worried about the script breaking things, but about it printing
>> spurious errors/warnings for unaffected setups.
> 
> Well, unaffected here would mean that all OSD LVs have autoactivation
> enabled (and are also activated). Additionally, if the OSDs are already
> up, `ceph-volume` doesn't do anything either.

no, unaffected here means 99% of the systems. and as soon as you run
commands on any system, there will be a small percentage where those
commands fail in noisy fashion for whatever reason. so the tradeoff
needs to be there - if the issue is big enough and the commands are not
very involved, then yes, fixing in postinst like this is a good idea.
for an issue that will affect almost nobody, and that requires running
commands with lots of storage interaction(!), that tradeoff looks rather
different..

> FWIW we could suppress LVM "No medium found" warnings in the LVM
> commands the script runs, like we do in pve-storage [0]. Additionally,
> we could also short-circuit and silently exit early if no changes are
> necessary; e.g. if autoactivation is enabled for all OSD LVs, we can
> assume that they're activated as well, and that the OSDs themselves are
> therefore running, too.
> 
> So, I would really prefer having either (an improved version of) the
> script, or some documentation regarding this *somewhere*, just to not
> leave any users in the dark.
> 
> [0]: https://git.proxmox.com/?p=pve-storage.git;a=blob;f=src/PVE/Storage/LVMPlugin.pm;h=0416c9e02a1d8255c940d2cd9f5e0111b784fe7c;hb=refs/heads/master#l21
> 
>>
>>
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> 
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