help with indices - what to index depending on server role

[<vgrig_us@hotmail.com>]

Hello

We're switching our college to openldap and I'm struggling a bit with 
decisions on indexing (all other parts - base functionality, replication, 
ACLs - are setup and working fine) . Maybe this list will help? What to 
index and why?

Our setup is as follows:

-----------------------------------------

a) 4 incoming MX servers running portfix. /etc/postfix/ldap-aliases.cf file 
is as follows:

server_host = ldap://localhost
               ldap://mailhub3
bind = no
search_base = dc=college, dc=edu
query_filter = mail=%s@college.edu
result_attribute = maildrop

-----------------------------------------

b) 2 outgoing smtp servers purring postfix and sasl. /etc/saslauthd.conf:

ldap_servers: ldaps://localhost/
ldap_auth_method: fastbind
ldap_filter: uid=%u,dc=college,dc=edu
ldap_tls_check_peer: no

-------------------------------------------

c) 2 radius servers for wifi authentication:

basedn = "dc=college,dc=edu"
filter = "(uid=%{%{Stripped-User-Name}:-%{User-Name}})"
password_attribute = userPassword

-------------------------------------------

d) IMAP servers - real unix users, using LDAP for system authentication - 
pretty standard setup.

pam_filter objectclass=posixAccount

---------------------------------------------

On all of these I have following indices:

index objectClass                       eq,pres
index ou,cn,mail,surname,givenname      eq,pres,sub
index uidNumber,gidNumber,loginShell    eq,pres
index uid,memberUid                     eq,pres,sub
index nisMapName,nisMapEntry            eq,pres,sub

I suspect I don't need some (or most) of them.

Thank you
- Vadim