6.1 Upgrade Appears to be Frozen when Migrating Events
Cb Response 6.x
While upgrading, a single node is taking significantly longer than the others to finish migrating events
The process documents on this node are far larger than the other minions so it is taking longer to process these documents.
This is normal behavior. It is rare, but migration process can take over an hour to complete.
Warning: Do not interrupt the upgrade process prior to this point or it could corrupt the new legacy core. If you have already done so, you can run a disk activity monitor such as iotop or iostats. If there is very little activity that could suggest core corruption: