Re: discuss about commit 3b0f9ce: filter-mpath: get wwids from sysfs vpd_pg83

On 11/13/23 19:38, David Teigland wrote:
> On Mon, Nov 13, 2023 at 02:52:39PM +0100, Peter Rajnoha wrote:
>> On 11/13/23 12:52, Martin Wilck wrote:
>>> I can't stress enough that this is *the only mechanism* that works
>>> correctly. udev serves as central hub to retrieve device properties
>>> from, and this is how it ought to be.
>>
>> Indeed, that was exactly one of the primary reasons the
>> 'external_device_info_source="udev"' was added. Reimplementing other
>> subsystem's logic is wrong because there's always some intrinsic logic
>> there that may be omitted. Sooner or later, such approach will fail.
>>
>> I agree with you here.
>>
>> If not sharing information through udev due to various kinds of hatred
>> about this part of the system, then alternatively, at least, calling a
>> multipath library function from LVM to do the job.
> 
> Hi, a number of things haven't been mentioned or noticed:
> 
> - In general, it's old versions of lvm that we're discussing here.
> Current lvm uses system.devices by default, where none of this is
> relevant.  We can just turn off a number of filters when system.devices is
> in use, including filter-mpath and filter-md.  It may still be interesting
> to look at improvements, but the context for that is older stable,
> released versions.

Hmm, but to generate or update the system.devices file and to add a new
entry there, we still need to check first whether it's a suitable device
or not, right? Like not being a multipath component...

-- 
Peter