Guidelines:

Should include

• Why do we only allow a shard to donate/receive one chunk at a time? E.g. to avoid frequent StaleShardVersions
• What is the serialization mechanism to make a shard only donate/receive one chunk at a time?
• What are the phases of the live migration (e.g. bulk clone, transfer mods, commit)
• Why do we update the ShardingStateRecovery document during migration and what is it used for?

Code references

• ActiveMigrationsRegistry class
• MigrationSourceManager class
• MigrationDestinationManager class
• ShardingStateRecovery class