keep checkpointing and archiving the logs (see checkpoint in slapd-bdb (5) and db_archive(1)), the disk occupation will not be impacted (apart for the storage where you archive the log files, of course).
Since 2.3 checkpoints correctly, if you set:
set_flags DB_LOG_AUTOREMOVE
--Quanah
-- Quanah Gibson-Mount Principal Software Developer ITSS/Shared Services Stanford University GnuPG Public Key: http://www.stanford.edu/~quanah/pgp.html