Reverse api in mongosync

Other MongoDB Topics
1

I have a DC and DR server,and inside another container mongosync is running.
Once i do run mongo sync,DC-DR is happening.

But if i do write in DR it shows right operation are disabled.(since i have used start api with reverse true,userWritesBlocked:true).

Suppose my DC is down,then what should i do?

What i tried is i did the commit on mongo sync container and hit reverse api
But it shows multiple error multiple times like:
… A request is already in progess.
… Currently in x state, needs to be in y state.

X,y represent various states.

Can anyone please explain the underlying mechanism behind this?

How do i handle failover cases with mongo sync.

Basically DR-DC.

THANK YOU.

2

update,
to enable write in DR,while my dc is down
db.adminCommand(
{
setUserWriteBlockMode: 1,
global: false
}
)

i did the baove command
but when my dc is up again,
how to get the data which i wrote in dr to dc.

can anyone please explain?

thanks