NeptuneMaster

The row range for a table is dynamically partitioned. Each row range is called a tablet, which is the unit of distribution and load balancing. The NeptuneMaster is responsible for assignment Tablet. When neptune cluster starts up. NeptuneMaster gets Tablet list from ROOT, META and assignes Tablet to TabletServer. When a tablet server is no longer serving its tablets, and for reassigning those tablets as soon as possible. Under NeptuneMaster failure, client can serve data service because NeptuneMaster doesn't have any information for data service.

TabletServer

The TabletServer is responsible for serving data and managing Tablet. A neptune cluster has multiple TabletServers, Each TabletServer is a dependent data service instance. A TabletServer manages thousands Tablet.

ChangeLogServer