Detail
How does metadata exchange during migrations affect memory?Answer
A node receiving migrations will spin up 1 thread per “migrate-max-num-incoming ”. Each of these threads will start queuing 300K buffers filled with metadata to transmit to the node sending the migration. If the network between nodes is somehow bandwidth limited, these queued buffers will start to pile up and use more memory.Unlike the emigrating records, there is no throttle based on outstanding bytes.
Recommendation is to keep migrate-max-num-incoming to reasonable values for the specific environment.