RPC CLIENT QUEUE TIME

RPC Client Port Queue Time

Average time that a RPC request (on the RPC port facing to the HDFS clients) waits in the queue.

RPC Client Port Queue Num Ops

Total number of RPC requests in the client port queue.

RPC CLIENT PORT PROCESSING TIME

RPC Client Port Processing Time

Average RPC request processing time in milliseconds, on the client port.

RPC Client Port Processing Num Ops

Total number of RPC active requests through the client port.

GC COUNT & GC TIME

GC Count

Shows the JVM garbage collection rate on the NameNode.

GC Time

Shows the garbage collection time in milliseconds.

GC PAR NEW

GC Count Par New

The number of times young generation garbage collection happened.

GC Time Par New

GC EXTRA SLEEP & WARNING THRESHOLD EXCEEDED

GC Extra Sleep Time

Indicates total garbage collection extra sleep time.

GC Warning Threshold Exceeded Count

Indicates number of times that the garbage collection warning threshold is exceeded

RPC CLIENT PORT QUEUE & BACKOFF

RPC Client Port Queue Length

Indicates the current length of the RPC call queue.

RPC Client Port Backoff

Indicates number of client backoff requests.

RPC SERVICE PORT QUEUE & NUM OPS

RPC Service Port Queue Time

Average time a RPC request waiting in the queue, in milliseconds. These requests are on the RPC port facing to the HDFS services, including DataNodes and the other NameNode.

RPC Service Port Queue Num Ops

Total number of RPC requests waiting in the queue. These requests are on the RPC port facing to the HDFS services, including DataNodes and the other NameNode.

RPC SERVICE PORT PROCESSING TIME & NUM OPS

RPC Service Port Processing Time

Average RPC request processing time in milliseconds, for the service port.

RPC Service Port Processing Num Ops

Number of RPC requests processed for the service port.

RPC SERVICE PORT CALL QUEUE LENGTH & SLOW CALLS

RPC Service Port Call Queue Length

The current length of the RPC call queue.

RPC Service Port Slow Calls

The number of slow RPC requests, for the service port.

TRANSACTIONS SINCE LAST EDIT & CHECKPOINT

Transactions Since Last Edit Roll

Total number of transactions since the last editlog segment.

Transactions Since Last Checkpoint

Total number of transactions since the last editlog segment checkpoint.

LOCK QUEUE LENGTH & EXPIRED HEARTBEATS

Lock Queue Length

Shows the length of the wait Queue for the FSNameSystemLock.

Expired Heartbeats

Indicates the number of times expired heartbeats are detected on NameNode.

THREADS BLOCKED / WAITING

Threads Blocked

Indicates the number of threads in a BLOCKED state, which means they are waiting for a lock.

Threads Waiting

Indicates the number of threads in a WAITING state, which means they are waiting for another thread to perform an action.