I understand that there is one Name Container per volume and number of data containers. When is the metadata about the data containers being written to Name Container? As far as I know, a file before being written to MapR-FS is broken down into chunks of 256MB each and each chunk is written to a master container, which gets replicated to an intermediate container and tail container. In this process, I did not see the metadata being written to Name Container. When is exactly the metadata is being written to Name Container? And how is the Name Container high availability assured?