MDB_MAP_FULL with plenty of free pages

Hello, We use OpenLDAP 2.4.57 under RHEL8 with a configuration with 2 directories in MM and 2 replicas. We only write on one of the masters. The size of the LMDB database grows following writes of members of large groups (2000 members) by a batch which runs every 10 minutes. The base grows regularly and sometimes undergoes significant jumps until it reaches its maximum size. The lmdb_stat -ef command indicates that very few pages are used and everything else is free pages. The used pages are stable. [cid:image001.jpg@01D720BD.58844450] And yet, it is no longer possible to write in the directory. Sometimes it's on the master directory, sometimes on replicas where syncrepl fails. 2021-03-24T11: 52: 59.978157 + 01: 00 int-ohz-infra1 slapd debug local4 25076 - mdb_id2entry_put: mdb_put failed: MDB_MAP_FULL: Environment mapsize limit reached (-30792) "uid = us-00000301, ou = users, dc = bst, dc = ocn, dc = infra, dc = ftgroup " 2021-03-24T11: 52: 59.978184 + 01: 00 int-ohz-infra1 slapd debug local4 25076 - syncrepl_null_callback: error code 0x50 2021-03-24T11: 52: 59.978202 + 01: 00 int-ohz-infra1 slapd debug local4 25076 - syncrepl_entry: rid = 001 be_modify failed (80) 2021-03-24T11: 52: 59.978780 + 01: 00 int-ohz-infra1 slapd debug local4 25076 - do_syncrepl: rid = 001 rc 80 retrying There is no transaction in progress: mdb_stat -r /var/lib/ldap/data/ Reader Table Status pid thread txnid 25076 7fa0e42c5480 - 25076 7fa0977fe700 - 25076 7fa097fff700 - 25076 7fa094cfa700 - 25076 7fa086ffe700 - 25076 7fa0857fb700 - 25076 7fa0867fd700 - 25076 7fa085ffc700 - 25076 7fa074ffc700 - The batch executes a lot of transactions < 2s. Restarting slapd does not resolve the problem. If we compact the database with mdb_copy -c, it only makes a few MB and it works again. The problem no longer appears without large groups. Why are free pages not used? Wouldn't there be a problem with writing many multi-valued attributes? Thank you for your help ! Jean-Charles Rogez [https://marketing.csnovidys.com/Logos/banniere_mail.png] [twitter icon]<https://twitter.com/csnovidys> [linkedin icon]<https://www.linkedin.com/company/novidy's> Jean-Charles ROGEZ Architecte Système | INTEGRATION SYSTEMES | PLESSIS Standard : +33180848010<tel:+33180848010> Ligne directe : <tel:r> Mobile : <tel:> Email : jean-charles.rogez@csnovidys.com<mailto:jean-charles.rogez@csnovidys.com>