Marc wrote:

To enable shared memmory I just do this?

In DB_CONFIG: set_shm_key 1

No.

And Put the slapd conf: olcDbShmKey to 1

No. Read the slapd-bdb(5) manpage.

And rebuild the bdb database in /var/lib/ldap/

You don't need to rebuild the database. Just run db_recover on the database.

I have a default (centos6) DB_CONFIG setup.

set_cachesize 0 268435456 1 set_lg_regionmax 262144 set_lg_bsize 2097152

I think if you had mounted the DB's filesystem with noatime or relatime that would also have removed the problem.