[ClusterLabs] Notifications on changes in clustered LVM

[Andrei Borzenkov]

20.06.2017 06:44, Digimer пишет:
> On 19/06/17 11:40 PM, Andrei Borzenkov wrote:
>> 20.06.2017 02:15, Digimer пишет:
>>> On 19/06/17 06:59 PM, Ferenc Wágner wrote:
>>>> Digimer <lists at alteeve.ca> writes:
>>>>
>>>>> So we have a tool that watches for changes to clvmd by running
>>>>> pvscan/vgscan/lvscan, but this seems to be expensive and occassionally
>>>>> cause trouble.
>>>>
>>>> What kind of trouble did you experience?
>>>>
>>>>> Is there any other way to be notified or to check when something
>>>>> changes?
>>>>
>>>> LV (de)activation generates udev events (due to block devices appearing/
>>>> disappearing).  PVs too, but they don't go though clvmd.
>>>>
>>>
>>> Interesting (dbus), I'll look into that.
>>>
>>
>> udev events are sent over netlink, not D-Bus.
> 
> I've not used that before. Any docs on how to listen for those events,
> by chance? If nothing off hand, don't worry, I can search.
> 

I do not think there is much documentation, checking (udev) source
remains the best option.

http://softengcrunch.blogspot.ru/2010/12/communicating-with-kernel-via-netlink.html
could be used as primer except you are interested in
NETLINK_KOBJECT_UEVENT protocol.