Amazon EMR
Amazon EMR Release Guide

Configuring an External Metastore for Hive

By default, Hive records metastore information in a MySQL database on the master node's file system. The metastore contains a description of the table and the underlying data on which it is built, including the partition names, data types, and so on. When a cluster terminates, all cluster nodes shut down, including the master node. When this happens, local data is lost because node file systems use ephemeral storage. If you need the metastore to persist, you must create an external metastore that exists outside the cluster.

You have two options for an external metastore: