Full_Name: Quanah Gibson-Mount Version: 2.4.47 OS: N/A URL: ftp://ftp.openldap.org/incoming/ Submission from: (NULL) (47.208.144.40)
There is currently an issue with back-mdb, where if the database is quite large (10GB+) and the environment is experiencing a heavy write load, that if you start a backup (slapcat or mdb_copy), the database will heavily fragment and grow significantly in size due to the read lock from the slapcat/mdb_copy process.
To work around this, slapcat could be given an option to honor the rtxnsize setting in slapd.conf/cn=config. This would allow the read lock to be released periodically and thus reduce the amount of fragmentation that occurs during the backup process. There is not (at this time) a solution proposed for mdb_copy.
It should be noted in the man page section for this option that the value of such a backup is of dubious quality, since it is no longer an exact "point in time" representation of the database but rather a bunch of different "point in times" stitched together into a single file.