Wasn't aware of this parameter, and couldn't find it in the administrator guide. Tried setting it to about the same as cachesize but it doesn't seem to have a huge effect. The first time the search runs after server-start-up, it still takes minutes to complete. Interestingly enough, CPU usage is very low during this time, below 10%, and even below 5% most of the time. iostat reports about 3.4% iowait.
Is there a way to verify that my indexes are working properly? As far as I can tell, they are present. There's an o.bdb and an objectclass.bdb in /var/lib/ldap. Also using loglevel 256 and not seeing any warnings in the log about unindexed attributes. I tried running slapindex again but that doesn't seem to have had any effect.