Dear list,
Thank you very much for your quick answer.
This question is actually due to a phenomenon that the customer got about a month ago. For the detail of the phenomenon, please see bellow.
-2008/11/16 The customer updated openldap package openldap-2.2.13-6.4E ⇒ openldap-2.2.13-12.el4
-2008/12/22 A problem happened, which doesn't need to be investigated this time, to the ldap server(server1), so that ldap service on server1 is temporary stopped and restarted.
-2008/01/06 The customer rearized that authorize requests by dovecot clients was all failed, and to know the reason the customer did some investigation. As a result, it was because of that dovecot accessed to only another server(server2) to authorize and server2 had not been replicated any data from server1 since 2008/11/16 which was shown by the replication log on server2(the last update was 2008/11/16). The server2 was supposed to have the same data as server1's which was latest data at that time by replication.
For this reason, the customer wants to know why dovecot accessed only server2 since ldap package was updated on 2008/11/16 and also wants to know why replication had been failed after updating the package. However, since the customer is not able to provide ehough information for this phenomenon because of their security policy, the customer said that only he wants to know this time is what the trigger to switch to another ldap server(between server1 and server2) and the way to specify which ldap server to access from the client as he wants if possible, or the specification of dovecot for accessing ldap servers in case there are more than one ldap servers pointed on 'hosts=' field in /etc/dovecot-ldap.conf
As you said, if both ldap servers are used ramdomly, it seems to be unusuall action that authorize request is failed all the time, it should be at least successful when authorizing by server1 since server1 has no problems after rebooting ldap service on 2008/12/22. I'm afraid, anything else that might be help or useful info to know the specification of dovecot?
Thanks,
Timo Sirainen さんは書きました:
On Jan 19, 2009, at 3:04 AM, Masaharu Kawada wrote:
In /etc/dovecot-ldap.conf, 'hosts=' field is the one which can be used to specify availabled ldap server to access from the clients to
authorize. And also sevral ldap servers can be specified in 'hosts =' field as
shown like below.hosts = ldap-server1.example.com ldap-server2.example.com
Dovecot simply passes these servers to the OpenLDAP library. It
doesn't do anything with them itself.※both server have the same configuration and available to
replication ldap-server1(master) to ldap-server2(slave).If this is right, how does dovecot know which ldap server is
currently used? and if the master dies, how does dovecot know and switch to slave one?I'm pretty sure that configuration will simply use both the servers
all the time more or less randomly. Unless OpenLDAP library has some
code that does something similar to what you're talking about, but
somehow I doubt that.
--
Masaharu Kawada Associate Global Support Engineer Red Hat K K Ebisu Neonato 8F 1-18 Ebisu 4-chome, Shibuya-ku Tokyo 150-0013, Japan Direct: +81-3-5798-8482