Mongosync cluster to cluster sync

MongoDB Atlas
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1

Hello MongoDB community. I have been doing mongosync cluster to cluster sync. So here is scenario I have prod and staging env. So I need to make backup and restore weekly basis so I am planning to use “mongosync” to do that since it will reduce cost comparatively to mongodump and restore. So i want to resume on saturday mongosync and pause on sunday. but while I was testing I was having an issue on oplog window from mongosync when I have paused it for 3-4 days I could not resume it again. Is there anyone who could help me in this case. so how much oplog window should I set up to cluster?

2

You should have enough oplog window to cover the time when mongosync is offline + some buffer. In your case sounds like 7-8 days should be a good start

3

One more question.Is oplog window refreshes within each process. I mean every week when we are making resume process in mongosync the oplog window of 8 days again becomes 8 day or no. So basically within resume command oplog window restarts again?

4

If you allow mongosync to fully catch up after the resume (i.e. replication lag reported by /progress API goes close to 0) then yes

5

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.

6

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?