LDAP redundancy at Freeradius 3.0.8

[Ing. Martin Samek]

Hi,

I'm trying find out how to correctly configure LDAP server redundacy in 
Freeradius 3.0.8. I dig trough mailing list archive, found some 
configuration snippets, but configuration doesn't work for me.

We have two LDAP servers in independent locations:

ldap.location1.tld.cz
ldap.location2.tld.cz

there is radius server radius.location1.tld.cz. Now I prepare 
configuration of radius.location2.tld.cz. My idea is to use 
ldap.location2 as primary LDAP server at radius.location2 and server 
ldap.location1 as fallback option in case that ldap.location2 is not 
available.

I added second section to the module ldap configuration:

ldap location1 {
     server = ldap.location1.tld.cz
     ...
     ...
}

ldap location2 {
     server = ldap.location2.tld.cz
     ...
     ...
}

according to this i altered site inner-tunnel configuration to

authorize {

location1
if ((ok || updated) && User-Password) {
     update {
         control:Auth-Type := mschap
     }
}

location2
if ((ok || updated) && User-Password) {
     update {
         control:Auth-Type := mschap
     }
}
}

but this didn't work for me. So i found in another thread piece of 
configuration with

redundant LDAP {
     location1
     location2
}

in authentication section there is:

Auth-Type LDAP {
         redundant LDAP {
             location1
             location2
         }
}

but also no luck. All cases leads to authentication fail when one of the 
ldap server is down. Could someone please explain me the point how 
correctly setup fail-over between these two LDAP server ?

Thanks.

Martin