Hi everyone, After a conversation with Colin McCabe and Proven Provenzano yesterday, we decided that the benefits outweigh the concerns with the overhead of associating a directory UUID to every replica in the metadata partition records. i.e. We prefer to always associate the log dir UUID even when only one log dir is configured in the broker.
This reduces complexity in several ways: * We no longer need to distinguish between JBOD and non JBOD modes when changing or when interpreting partition metadata. * Determining whether a replica is online through the metadata cache no longer depends on the number of registered log directories. * We can get rid of edge cases in the transition in or out of multi log dir configuration, where the Controller would have to update a lot of replica assignments. * The OfflineLogDirs field in the broker registration is no longer necessary. So I'm updating the KIP with the following changes: - "Directory" is no longer a tagged field in PartitionRecord and PartitionChangeRecord - "OfflineLogDirs" is removed from BrokerRegistrationRequest, RegisterBrokerRecord and BrokerRegistrationChangeRecord - "OnlineLogDirs" is renamed to "LogDirs" in BrokerRegistrationRequest, RegisterBrokerRecord and BrokerRegistrationChangeRecord -- Igor
