See Metrics for an introduction and how to enable Metrics emission.
Block cache item count in memory. This is the number of blocks of StoreFiles (HFiles) in the cache.
Number of blocks that had to be evicted from the block cache due to heap size constraints.
Block cache hit caching ratio (0 to 100). The cache-hit ratio for reads configured to look in the cache (i.e., cacheBlocks=true).
Number of blocks of StoreFiles (HFiles) read from the cache.
Block cache hit ratio (0 to 100). Includes all read requests, although those with cacheBlocks=false will always read from disk and be counted as a "cache miss".
Number of blocks of StoreFiles (HFiles) requested but not read from the cache.
Block cache size in memory (bytes). i.e., memory in use by the BlockCache
Size of the compaction queue. This is the number of Stores in the RegionServer that have been targeted for compaction.
Number of enqueued regions in the MemStore awaiting flush.
Filesystem read latency (ms). This is the average time to read from HDFS.
Filesystem sync latency (ms). Latency to sync the write-ahead log records to the filesystem.
Number of operations to sync the write-ahead log records to the filesystem.
Filesystem write latency (ms). Total latency for all writers, including StoreFiles and write-head log.
Number of filesystem write operations, including StoreFiles and write-ahead log.
Total number of read and write requests. Requests correspond to RegionServer RPC calls, thus a single Get will result in 1 request, but a Scan with caching set to 1000 will result in 1 request for each 'next' call (i.e., not each row). A bulk-load request will constitute 1 request per HFile.
Sum of all the StoreFile index sizes in this RegionServer (MB)
Number of Stores open on the RegionServer. A Store corresponds to a ColumnFamily. For example, if a table (which contains the column family) has 3 regions on a RegionServer, there will be 3 stores open for that column family.