[Samba] PDC BDC hot failover

Florian Zierer ziererf at in.tum.de
Fri Jan 19 14:29:36 GMT 2007

Hi Felipe,

Felipe Augusto van de Wiel wrote:

> On 01/17/2007 07:32 AM, Florian Zierer escreveu:
>> Hi there,
>> I have a problem getting my Samba installation redundant.
>> I installed a PDC and a BDC working with 2 LDAP servers.
>> The problem is, when users are logged in and the BDC fails, 
>> the PDC does not take over the running sessions and vice versa.
> 	And it shouldn't. :-)

Ah, ok. Thanks for the clarification. I have nowhere read something like 
a table about the features of a bdc.

Perhaps this would be good to mention in the official samba howto at 
There is something written about bdcs but it would be good to have a 
section like:

What does it do?
	- load balancing
	- logons still possible if one dc fails
	- ...

What does it NOT do?
	- take over running session
	- ...

There is so much Samba Documentation out there but it is difficult to 
find the right answers.

What are the differences between a BDC and a PDC?

> 	PDC/BDC strategy is used to share the load and keep your
> network running logons and so on, if you have a common backend
> then you can share the files and work something like a High
> Avaliability or CLustered environment.

perhaps this should also be written on the official howto.

There is not that much written about failure scenarios and redundancy.
What is going on if my pdc and the master ldap server fail.
Can the bdc still operate with the slave ldap?

What is going on if the machine trust passwords are changed in such a 

Do i have to "propagate" the bdc to a pdc (in smb.conf)?

 >> The clients have a hanging explorer and so on.
 >> When the failing server gets back online again, everything
 >> works, no lags anymore.

 >	Exactly, so it seems to be working the way it should be.


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