Live Migration - what happens if if you miss the "Cut Over" window?

I initiated a live migration over the weekend and everything seems fine. I extended the cutover window once and then forgot about it and missed actually clicking the “Cut Over” button. Based on the help docs, pressing “Cut Over” does this:

  1. Mark the migration plan as complete.
  2. Remove the Application Server subnets from the destination cluster whitelist.
  3. Remove the MongoDB user that Live Migrate used to import data to the destination cluster.

These steps sound internal to the live migration tool but also don’t sound like they would impact my application if they got missed. Should I be worried about anything?

Hi @Steven_Chan,

Welcome to the community!

Regarding your question in the title:

what happens if if you miss the “Cut Over” window?

As per the Live Migrate documentation, If the 72 hour period passes, Atlas stops synchronizing with the source cluster. This would be the same case if you had extended the timer and let the new time expire also.

Should I be worried about anything?

The sync destination would not have any changes made to it from the sync source from the time the cut over timer expired.

Hope this answers your questions.

Kind Regards,


Thanks Jason! So it’s pretty much as though I hit the “Cut Over” button at the point when the window passed? For instance, nothing gets rolled back right? I gather the resultant error message at next login is just scarier than the true situation since it reports that the migration failed and that’s what got me worried.

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