When a es node (es 0.90.7) restart, the restarted node will rebuild shards using peers replica. Is the rebuild from size 0byte until it is balance with other peers? Why is this done so? is it because of the stale data even within few second restart?
Another question is, considering full cluster restart during upgrade. What's gonna happen to the data in the cluster? Will the cluster think all the data are stale and wipe all the data in this situation?