MMR has supported delta-syncrepl since 2.4.27. You should use it.
I did consider delta-syncrepl, but given the high write load expected, I was not sure if it was the right decision. I am expecting an average load of 50-100 writes per second, and with 1 backup provider, and 10 consumers, it might get heavy on the provider which is serving the writes, given that OpenLDAP would be maintaining another DB for the access log.
But with this syncrepl issue, it looks like I need to change the replication mode to refreshAndPersist anyway. As such it looks like delta syncrepl is also refreshAndPersist too.
Is there any recommendation between simple refreshAndPersist and delta-syncrepl with refreshAndPersist for high write loads?
Thanks
PS: I see that delta syncrepl is compatible with MMR which I presume to be MultiMaster. I hope it works with Mirror Mode too. I did not find any documents supporting this.