bulk load speeds bdb vs ldbm

["Mark J Strawcutter" <mjstraw@iup.edu>]

We run an OpenLDAP server to provide a "white pages" directory
that is queried by email clients and a web look-up form.  Nothing
complicated, complete reload of the database each night using
an extract from out student/employee records system.

ldbm has been working fine.  We can reload all 30k entries in
a couple of minutes using slapadd.

Common wisdom seems to be that bdb is better, so I'm investigating
switching.  The first problem is that the load takes 2-3 hours :-(
The slapd.conf params I've found that look like they might help
have been set thusly:

cachesize       100000
idlcachesize    1000000

Any suggestions on what I can do to bring bdb load times more in line
with ldbm?  Or should I just stick with what's working (ie ldbm)?

Mark