we have 3 node cluster each at primary and secondary site. normally we do delta replication from primary to secondary. everything works fine.
due to disaster secondary was up. and data is coming to secondary site.
now when primary site is functional and up, we have shifted all the services from secondary to primary.
at this point
for the past few days when primary was down, data count in secondary is greater than primary (primary data count is zero) for those days.
and now when we have started delta replication from primary to secondary, suddenly all the data which was there in secondary site is deleted.
ideally delta replication should only copy the data which is not in secondary and available in primary. and it should not delete any data at any cost.
Ideally it should be like below. on day 6 services are running from PR and delta replication is started from PR to DR.
Day1 Site/DataCount Site/DataCount
1 PR/100 DR/100
2 PR/100 DR/100
3 PR/0 DR/100
4 PR/0 DR/100
5 PR/0 DR/100
6 PR/100 DR/100
7 PR/100 DR/100
After disaster fix, we started replication from PR to DR.
Below is the situation we are currently facing. all the data in secondary for days (3,4,5) is deleted.
Day1 Site/DataCount Site/DataCount
1 PR/100 DR/100
2 PR/100 DR/100
3 PR/0 DR/0
4 PR/0 DR/0
5 PR/0 DR/0
6 PR/100 DR/100
7 PR/100 DR/100
why is this strange behaviour ? are we missing something ? how do we prevent vbr from deleting any data ? do we need to tune something ?