Good day,
Additionally, for a BDB backend, you can also back up the database files
while slapd is running. This is less resource intensive and works well
for a large database.
The procedure I've used, gathered from the Sleepycat page, is basically:
1) Copy your .bdb files and your DB_CONFIG file to a backup location.
There's a sleepycat tool to identify db files in a directory, but it won't
identify some files in some certain situations, so I believe it's best
just to grab files by extension.
2) THEN copy your "log" files, lowest IDs first, to the same location.
The order of copying is crucial!
Make absolutely sure you run slapd_db_recover on this data prior to
starting slapd (this is a good idea to do anyway)!