is it safe to have two backed used for the same user?

[lejeczek]

On 23/06/15 15:41, Steffen Kaiser wrote:
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> On Tue, 23 Jun 2015, Steffen Kaiser wrote:
>> On Tue, 23 Jun 2015, lejeczek wrote:
>>
>>> I wonder if it is safe (and wise) to have two passw-user 
>>> databases for the
>>> same one user.
>>> I'm thinking,
>>> mail to me via pam
>>> mail to me at this.domain via ldap
>>
>> the first passdb wins. No problem.
>>
>>> whole Maildir would be essentially the same one storage 
>>> target, I see
>>> permissions have to be mangled, available to write for 
>>> both vmail and actual
>>> uid.
>>
>> again, the first userdb wins. Your users can auth agains 
>> pam, but the data
>> may come from LDAP or a static userdb.
>> If you auth agains PAM successfully, does _not_ mean that 
>> you
>> automatically use system users or Dovecot changes uids or 
>> something. All
>> such information come from the userdb. If both users 
>> match the same userdb
>> entry, they appear the same for Dovecot.
>
> To make it more clear:
>
> you can have
>
> passdb { driver = pam }
> passdb { driver = ldap
>   ...
> }
>
> userdb { driver = ldap
>     ....
> }
>
> you do not need no userdb { driver = passwd }, unless you 
> require user data from this source. Or use userdb { driver 
> = static } instead the LDAP one, because you do not use 
> LDAP attributes anyway.
OK, I see,
can a querying pam backed be custom? eg. how does one looks 
up me at some.thing ?
many thanks Steffen for all your help.
>
> - -- Steffen Kaiser
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