How to reinitialize IDM Replica RHEL/Rocky 8,9,10

IDM replicas can stop replicating correctly when an error occurs. This can happen when the connection between replicas stops for a short time and the same objects get edited on both sides (split brain).

On the unsynced replica an error might look something like this:

[root@idm4 ~]# tail -f /var/log/dirsrv/slapd-THUB-LOCAL/errors
[21/Aug/2025:10:48:37.723548950 +0200] - ERR - agmt="cn=idm4.thub.local-to-bnidm4.thub.local" (bnidm4:389) - clcache_load_buffer - Can't locate CSN 6762db37000000190000 in the changelog (DB rc=-12797). If replication stops, the consumer may need to be reinitialized.

In my case THUB.LOCAL is my domain and idm4 is the replica that lost the replication agreement to bnidm4.

The replica can be re-initialized with this command:

[root@idm4 ~]# ipa-replica-manage re-initialize --from=bnidm4.thub.local
Directory Manager password:

Update in progress, 4 seconds elapsed
Update succeeded

Make sure you execute the command on the correct host since configuration might get overwritten.