db.oplog.rs.stats()
{
        "ns" : "local.oplog.rs",
        "count" : 7416525,
        "size" : 10737295893,
        "avgObjSize" : 1447,
        "storageSize" : 149559255040,
        "capped" : true,
        "max" : -1,
        "maxSize" : NumberLong("10737418240"),
        "wiredTiger" : {
                "metadata" : {
                        "formatVersion" : 1,
                        "oplogKeyExtractionVersion" : 1
                },
                "creationString" : "allocation_size=4KB,app_metadata=(formatVersion=1,oplogKeyExtractionVersion=1),block_allocation=best,block_compressor=zlib,cache_resident=0,checkpoint=(WiredTigerCheckpoint.874489=(addr=\"01e40136055a81e419d8847fe4022d0326c0e5e4746768cde4022c1493c0ade4a53eb837808080e522d26cffc0e523898cafc0\",order=874489,time=1500253703,size=152631562240,write_gen=67446065)),checkpoint_lsn=(42287,71868672),checksum=uncompressed,collator=,columns=,dictionary=0,format=btree,huffman_key=,huffman_value=,id=9,internal_item_max=0,internal_key_max=0,internal_key_truncate=,internal_page_max=4KB,key_format=q,key_gap=10,leaf_item_max=0,leaf_key_max=0,leaf_page_max=32KB,leaf_value_max=1MB,memory_page_max=10m,os_cache_dirty_max=0,os_cache_max=0,prefix_compression=0,prefix_compression_min=4,split_deepen_min_child=0,split_deepen_per_child=0,split_pct=90,value_format=u,version=(major=1,minor=1)",
                "type" : "file",
                "uri" : "statistics:table:local/collection/6--5846934347363493562",
                "LSM" : {
                        "bloom filters in the LSM tree" : 0,
                        "bloom filter false positives" : 0,
                        "bloom filter hits" : 0,
                        "bloom filter misses" : 0,
                        "bloom filter pages evicted from cache" : 0,
                        "bloom filter pages read into cache" : 0,
                        "total size of bloom filters" : 0,
                        "sleep for LSM checkpoint throttle" : 0,
                        "chunks in the LSM tree" : 0,
                        "highest merge generation in the LSM tree" : 0,
                        "queries that could have benefited from a Bloom filter that did not exist" : 0,
                        "sleep for LSM merge throttle" : 0
                },
                "block-manager" : {
                        "file allocation unit size" : 4096,
                        "blocks allocated" : 30903430,
                        "checkpoint size" : 152631562240,
                        "allocations requiring file extension" : 1296614,
                        "blocks freed" : 25543549,
                        "file magic number" : 120897,
                        "file major version number" : 1,
                        "minor version number" : 0,
                        "file bytes available for reuse" : 504307712,
                        "file size in bytes" : 149559255040
                },
                "btree" : {
                        "btree checkpoint generation" : 429555,
                        "column-store variable-size deleted values" : 0,
                        "column-store fixed-size leaf pages" : 0,
                        "column-store internal pages" : 0,
                        "column-store variable-size leaf pages" : 0,
                        "pages rewritten by compaction" : 0,
                        "number of key/value pairs" : 0,
                        "fixed-record size" : 0,
                        "maximum tree depth" : 4,
                        "maximum internal page key size" : 368,
                        "maximum internal page size" : 4096,
                        "maximum leaf page key size" : 3276,
                        "maximum leaf page size" : 32768,
                        "maximum leaf page value size" : 1048576,
                        "overflow pages" : 0,
                        "row-store internal pages" : 0,
                        "row-store leaf pages" : 0
                },
                "cache" : {
                        "bytes read into cache" : NumberLong("3850014232885"),
                        "bytes written from cache" : NumberLong("4027624357716"),
                        "checkpoint blocked page eviction" : 1161085,
                        "unmodified pages evicted" : 8215686,
                        "page split during eviction deepened the tree" : 0,
                        "modified pages evicted" : 22280545,
                        "data source pages selected for eviction unable to be evicted" : 26634717,
                        "hazard pointer blocked page eviction" : 22965569,
                        "internal pages evicted" : 218785,
                        "pages split during eviction" : 4128192,
                        "in-memory page splits" : 1445,
                        "overflow values cached in memory" : 0,
                        "pages read into cache" : 27243649,
                        "overflow pages read into cache" : 1183,
                        "pages written from cache" : 30084968
                },
                "compression" : {
                        "raw compression call failed, no additional data available" : 2034106,
                        "raw compression call failed, additional data available" : 210907,
                        "raw compression call succeeded" : 33617030,
                        "compressed pages read" : 26963420,
                        "compressed pages written" : 721249,
                        "page written failed to compress" : 2,
                        "page written was too small to compress" : 767398
                },
                "cursor" : {
                        "create calls" : 2499,
                        "insert calls" : 1319355924,
                        "bulk-loaded cursor-insert calls" : 0,
                        "cursor-insert key and value bytes inserted" : NumberLong("2862189380167"),
                        "next calls" : 2678675450,
                        "prev calls" : 57305,
                        "remove calls" : 28541616,
                        "cursor-remove key bytes removed" : 256874544,
                        "reset calls" : 1603760914,
                        "search calls" : 200610980,
                        "search near calls" : 57211446,
                        "update calls" : 0,
                        "cursor-update value bytes updated" : 0
                },
                "reconciliation" : {
                        "dictionary matches" : 0,
                        "internal page multi-block writes" : 236028,
                        "leaf page multi-block writes" : 4420086,
                        "maximum blocks required for a page" : 88,
                        "internal-page overflow keys" : 0,
                        "leaf-page overflow keys" : 0,
                        "overflow values written" : 431,
                        "pages deleted" : 9925972,
                        "page checksum matches" : 1968486,
                        "page reconciliation calls" : 25343235,
                        "page reconciliation calls for eviction" : 23052320,
                        "leaf page key bytes discarded using prefix compression" : 0,
                        "internal page key bytes discarded using suffix compression" : 0
                },
                "session" : {
                        "object compaction" : 0,
                        "open cursor count" : 2499
                },
                "transaction" : {
                        "update conflicts" : 0
                }
        },
        "nindexes" : 0,
        "totalIndexSize" : 0,
        "indexSizes" : {

        },
        "ok" : 1,
        "$gleStats" : {
                "lastOpTime" : Timestamp(0, 0),
                "electionId" : ObjectId("57e2f7739c87007ce802ce27")
        }
}