If you are going to flog ChronicDB, please at least disclose if you have some sort of relationship with said company. Most of your previous submissions pertain to ChronicDB.
A couple of limitations of the Percona tool are related to changing data in tables with ON DELETE and ON UPDATE foreign key constraints and possible lock-ups of tables. It is a bi-directional replication tool, so it has to deal with the master-master replication case and as such does not guarantee data consistency.
Still the tool is helpful in many cases and congrats to Percona for developing it. Replication safety is a non-trivial problem in general.
The author of the 6b article kindly provided more information about the time it took for the migration:
http://news.ycombinator.com/item?id=3621561
A couple of limitations of the Percona tool are related to changing data in tables with ON DELETE and ON UPDATE foreign key constraints and possible lock-ups of tables. It is a bi-directional replication tool, so it has to deal with the master-master replication case and as such does not guarantee data consistency.
Still the tool is helpful in many cases and congrats to Percona for developing it. Replication safety is a non-trivial problem in general.