The MDS is a server daemon that manages the meta-data of the GFS Shared File System and operates as a user process. There are two processes of primary MDS and secondary MDS for each file system. Two nodes of those that shares a file system are predefined as MDS nodes and MDS operates on one of these nodes. The MDS nodes are only the two nodes of the primary and secondary MDS node.
The secondary MDS is used for standby and runs on a different node from the primary MDS. However, when only one of MDS nodes is active, the secondary MDS does not run. The MDS uses multithreading in order to execute processing requests from AC in parallel.
The MDS has the following major functions:
