Symptoms

Sometimes we run into a situation where we have to force Sync a certain volume. 

Purpose

This article is to discuss more regarding Force Sync, its usage and its side effects

Resolution

What  Force Sync actually does?

 Foce Sync is a SnapReplication Action where a volume will be totally removed from the target node ( that includes all of the automatic and the manual snapshots) then it will start mirroring this volume from the beginning, and that will take some time depending on the volume size.

When to use Force Sync?
Usually, Force Sync is used when there is a severe error with replication that leads to total failure and to a non-returning state, usually when "Replicate Now" fails to fix those errors, so we use Force Sync as a last resort to fix such issues. 

Who is supposed to do a Force Syn?
It should be used by Buurst support team or after discussing the issue with them. As it is usually required after a certain failure, and we would like to have a close look at the system to clearly understand what lead us to such a situation

Force Sync comes with a cost
1- You will start mirroring your data from the beginning, which may take days depending on your data, the connection speed between nodes, and any throttling settings
2- During the time for force-sync you have only one copy of data on one node, so you are exposed to downtime in case of any failure happens to the other node
3- Performance penalty, as mirroring all the data to another node is resource-intensive especially if not throttling being set