[Samba] When and how often are elections held for LMB?

[Uriel Avalos]

Can someone clarify this for me? The docs are not clear. It seems that an election is held when:

* There is no LMB or the current LMB shuts down. 
* A machine joins the network with "preferred master = yes" and forces an election.

Any other times when an election is held?

What's also not clear is how OFTEN the election is held. The how-to makes a passing reference that "two machines with "preferred master = yes" will periodically force election." Is that true? I thought that elections were only held when there is no LMB or only when a preferred master boots up.