On 8.4.2014, at 16.54, Daniel Parthey <d.parthey@metaways.de> wrote:
the Dovecot Director determines the backend host in some way by hashing the username:
http://wiki2.dovecot.org/Director
For normal logins username@example.org, the director always gets the same hash for the same username and ensures that the login is always proxied to the same backend.
But what about MasterUsers in combination with Dovecot Director?
http://wiki2.dovecot.org/Authentication/MasterUsers
Which configuration directives should be used to make sure that logins
username@example.org*masteruser1@example.org username@example.org*masteruser2@example.org username@example.org*masteruser3@example.org
go to the same mailbox backend, in order to avoid NFS caching conflicts for mailbox username@example.org which should always reside on the same NFS client?
Is the master user cut off from behind the master_user_separator?
Yes, assuming your director (not backend) is configured with auth_master_user_separator=*. It's translated into SASL PLAIN authentication for backends where director hashes only the username.
How is the director hash exactly calculated? Can the director hashing algorithm be configured in some way?
director_username_hash can be used for configuring.
BTW. There are also some kludgy things you can do with this if you need some weird setup, such as using user@domain1@domain2 style usernames where director_username_hash = %{username}@%{domain_first} and then you can use the %{domain_last} variable in the backend to do some extra stuff. For example if you want to have @readonly user with readonly ACLs.