Hello!
slapd.conf configuration used
1.    I have test LDAP master and a consumer with LDAP Sync Replication type:
Master:
    overlay syncprov
    syncprov-checkpoint 100 10
    syncprov-sessionlog 100

Consumer:
    syncrepl rid=115        provider=ldaps://master \
                        type=refreshOnly \
                        interval=00:00:00:30 \
                        scope=sub \
                        schemachecking=off \
                        searchbase="dc=exadel,dc=com" \
                        bindmethod=simple \
                        binddn="dc=exadel,dc=com" \
                        credentials=password \
                        retry="60 10 300 10"
Sync is work.

2.    After that I have switched to MirrorMode replication via reconfiguring Master and Consumer:
Master1(Master):
    serverID    1
    overlay syncprov
    syncprov-checkpoint 100 10
    syncprov-sessionlog 100

     syncrepl rid=001    provider=ldaps://Master2 \
                    bindmethod=simple \
                    interval=00:00:00:30 \
                    scope=sub \
                    binddn="dc=exadel,dc=com" \
                    credentials=password \
                    searchbase="dc=exadel,dc=com" \
                    schemachecking=off \
                    type=refreshOnly \
                    retry="60 +"

    mirrormode on

Master2(Consumer):

    serverID    2
    overlay syncprov
    syncprov-checkpoint 100 10
    syncprov-sessionlog 100

     syncrepl rid=002    provider=ldaps://Master1 \
                    bindmethod=simple \
                    interval=00:00:00:30 \
                    scope=sub \
                    binddn="dc=exadel,dc=com" \
                    credentials=password \
                    searchbase="dc=exadel,dc=com" \
                    schemachecking=off \
                    type=refreshOnly \
                    retry="60 +"

    mirrormode on

In this case SYNC is work(between Master1 -> Master2(NOT in Master2) -> Master1 direction) and other consumer pointed to Master1 or Master2)

3.    For fun I change configuration on Master1(Master) to previous state(Case 1)
Master1:
    overlay syncprov
    syncprov-checkpoint 100 10
    syncprov-sessionlog 100

Master2(Consumer):

    serverID    2
    overlay syncprov
    syncprov-checkpoint 100 10
    syncprov-sessionlog 100

     syncrepl rid=002    provider=ldaps://Master1 \
                    bindmethod=simple \
                    interval=00:00:00:30 \
                    scope=sub \
                    binddn="dc=exadel,dc=com" \
                    credentials=password \
                    searchbase="dc=exadel,dc=com" \
                    schemachecking=off \
                    type=refreshOnly \
                    retry="60 +"

    mirrormode on

In this case we have the same situation with SYNC as in CASE 2 - all work fine.

Is it good working SYNC schema? What chance of breaking down db on Master1 I have?

-- 
With Best Wishes
Andrei Valoshyn
Exadel Inc. 
System Administrator
avaloshyn@exadel.com

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