Logging Region out of memory

I just started getting this early this morning. I set this server up a number of years ago. I am getting ready to put a new one in place, but need to get this back up and going in the mean time.

Openldap version is 2.4.12

/sbin/service ldap start

Checking configuration files for slapd: [FAILED] Logging region out of memory; you may need to increase its size db_open(/var/lib/ldap/id2entry.bdb) failed: Cannot allocate memory (12). backend_startup_one: bi_db_open failed! (12) slap_startup failed (test would succeed using the -u switch) stale lock files may be present in /var/lib/ldap [WARNING]

Any ideas on what I need to check there? Thanks.