# Machine-Readable Status

FoundationDB provides status information in machine-readable JSON form (in addition to the human-readable form made available by the command line interface). This document explains how to access the machine-readable status, provides guidance for its use, and describes the JSON format used to encode it.

## Accessing machine-readable status

You can access machine-readable status in three ways ways:

- Within `fdbcli`, issue the command `status json`. This command will output status information in JSON (rather than the human-readable format output by `status` and `status details`). See the status command for more information.

- From a command shell, use fdbcli by running `fdbcli --exec "status json"`

- From any client, read the key `\xFF\xFF/status/json`. The value of this key is a JSON object serialized to a byte string with UTF-8 encoding. In Python, given an open database `db`, the JSON object can be read and deserialized with:

      import json
      status = json.loads(db['\xff\xff/status/json'])

## Guidance regarding versioning

The JSON format of the machine-readable status is not considered part of our API and, in particular, is not governed by the versioning mechanism used to facilitate API upgrades. A client that makes use of the machine-readable status should be prepared to handle possible format changes across versions.

Format changes will be governed as follows:

- We will not make arbitrary changes to the JSON format; we will make such changes only as required by changes in the underlying system characteristics relevant to status reporting.

- We may add fields as needed to report new categories of data.

- We may remove a field if a new version of FoundationDB renders the field obsolete.

- We will not change the semantics of an existing field. If the data relating to a field changes in a manner that is incompatible with previous usage, the field will be deleted and replaced by a newly named field.

## JSON format

The following format informally describes the JSON containing the status data. The possible values of `<name_string>` and `<description_string>` are described in Message components. The format is representative: any field can be missing at any time, depending on the database state. Clients should be prepared to flexibly handle format variations resulting from different database states.

    "cluster":{
         "storage_wiggler": {
             "wiggle_server_ids":["0ccb4e0feddb55"],
             "wiggle_server_addresses": ["127.0.0.1"],
             "primary": { // primary DC storage wiggler stats
                 // One StorageServer wiggle round is considered 'complete', when all StorageServers with creationTime < T are wiggled
                "last_round_start_datetime": "2022-04-02 00:05:05.123 +0000",
                "last_round_start_timestamp": 1648857905.123, // when did the latest round start
                "last_round_finish_datetime": "1970-01-01 00:00:00.000 +0000",
                "last_round_finish_timestamp": 0, // when did the latest finished round finish
                "smoothed_round_seconds": 1, // moving average duration of a wiggle round
                "finished_round": 1,
                // 1 wiggle step as 1 storage server is wiggled in the current round
                "last_wiggle_start_datetime": "2022-04-02 00:05:05.123 +0000",
                "last_wiggle_start_timestamp": 1648857905.123, // when did the latest wiggle step start
                "last_wiggle_finish_datetime": "1970-01-01 00:00:00.000 +0000",
                "last_wiggle_finish_timestamp": 0,
                "smoothed_wiggle_seconds": 1,
                "finished_wiggle": 1
             },
             "remote": { // remote DC storage wiggler stats
                "last_round_start_datetime": "2022-04-02 00:05:05.123 +0000",
                "last_round_start_timestamp": 1648857905.123,
                "last_round_finish_datetime": "1970-01-01 00:00:00.000 +0000",
                "last_round_finish_timestamp": 0,
                "smoothed_round_seconds": 1,
                "finished_round": 1,
                "last_wiggle_start_datetime": "2022-04-02 00:05:05.123 +0000",
                "last_wiggle_start_timestamp": 1648857905.123,
                "last_wiggle_finish_datetime": "1970-01-01 00:00:00.000 +0000",
                "last_wiggle_finish_timestamp": 0,
                "smoothed_wiggle_seconds": 1,
                "finished_wiggle": 1
             }
        },
       "layers":{
          "_valid":true,
          "_error":"some error description"
       },
       "processes":{
          "$map_key=zoneid":{
             "version":"3.0.0", // a process version will not be reported if it is not protocol-compatible; it will be absent from status
             "machine_id":"0ccb4e0feddb5583010f6b77d9d10ece",
             "locality":{ // This will contain any locality fields that are provided on the command line
                 "$map_key=localityName":"value"
             },
             "class_source":{
                "$enum":[
                   "command_line",
                   "configure_auto",
                   "set_class"
                ]
             },
             "class_type":{
                "$enum":[
                   "unset",
                   "storage",
                   "transaction",
                   "resolution",
                   "stateless",
                   "commit_proxy",
                   "grv_proxy",
                   "master",
                   "test",
                   "storage_cache"
                ]
             },
             "degraded":true,
             "roles":[
                {
                   "query_queue_max":0,
                   "local_rate":0,
                   "input_bytes":{
                      "hz":0.0,
                      "counter":0,
                      "roughness":0.0
                   },
                   "stored_bytes":12341234,
                   "kvstore_used_bytes":12341234,
                   "kvstore_available_bytes":12341234,
                   "kvstore_free_bytes":12341234,
                   "kvstore_total_bytes":12341234,
                   "kvstore_total_size":12341234,
                   "kvstore_total_nodes":12341234,
                   "kvstore_inline_keys":12341234,
                   "durable_bytes":{
                      "hz":0.0,
                      "counter":0,
                      "roughness":0.0
                   },
                   "queue_disk_used_bytes":12341234,
                   "queue_disk_available_bytes":12341234,
                   "queue_disk_free_bytes":12341234,
                   "queue_disk_total_bytes":12341234,
                   "role":{
                      "$enum":[
                         "master",
                         "commit_proxy",
                         "grv_proxy",
                         "log",
                         "storage",
                         "resolver",
                         "cluster_controller",
                         "data_distributor",
                         "ratekeeper",
                         "storage_cache",
                         "router",
                         "coordinator"
                      ]
                   },
                   "tss":false,
                   "storage_metadata":{
                      "created_time_datetime":"1970-01-01 00:00:00.000 +0000",
                      "created_time_timestamp": 0,
                      "storage_engine":{
                      "$enum":[
                      "ssd",
                      "ssd-1",
                      "ssd-2",
                      "ssd-redwood-1",
                      "ssd-rocksdb-v1",
                      "ssd-sharded-rocksdb",
                      "memory",
                      "memory-1",
                      "memory-2",
                      "memory-radixtree-beta",
                      "unknown"
                      ]}
                   },
                   "rocksdb_metrics":{
                      "block_cache_hits":12341234,
                      "block_cache_misses":12341234,
                      "pending_compaction_bytes":12341234,
                      "memtable_bytes":12341234,
                      "sst_reader_bytes":12341234,
                      "block_cache_usage":12341234,
                      "block_cache_limit":12341234,
                      "throttled_commits":12341234,
                      "write_stall_microseconds":12341234
                   },
                   "data_version":12341234,
                   "durable_version":12341234,
                   "data_lag": {
                      "seconds":5.0,
                      "versions":12341234
                   },
                   "durability_lag": {
                      "seconds":5.0,
                      "versions":12341234
                   },
                   "id":"eb84471d68c12d1d26f692a50000003f",
                   "total_queries":{
                      "hz":0.0,
                      "counter":0,
                      "roughness":0.0
                   },
                   "finished_queries":{
                      "hz":0.0,
                      "counter":0,
                      "roughness":0.0
                   },
                   "low_priority_queries":{
                      "hz":0.0,
                      "counter":0,
                      "roughness":0.0
                   },
                   "bytes_queried":{
                      "hz":0.0,
                      "counter":0,
                      "roughness":0.0
                   },
                   "keys_queried":{
                      "hz":0.0,
                      "counter":0,
                      "roughness":0.0
                   },
                   "mutation_bytes":{
                      "hz":0.0,
                      "counter":0,
                      "roughness":0.0
                   },
                   "mutations":{
                      "hz":0.0,
                      "counter":0,
                      "roughness":0.0
                   },
                   "fetched_versions":{
                      "hz":0.0,
                      "counter":0,
                      "roughness":0.0
                   },
                   "fetches_from_logs":{
                      "hz":0.0,
                      "counter":0,
                      "roughness":0.0
                   },
                   "grv_latency_statistics":{ // GRV Latency metrics are grouped according to priority (currently batch or default).
                      "default":{
                          "count":0,
                          "min":0.0,
                          "max":0.0,
                          "median":0.0,
                          "mean":0.0,
                          "p25":0.0,
                          "p90":0.0,
                          "p95":0.0,
                          "p99":0.0,
                          "p99.9":0.0
                      },
                      "batch":{
                          "count":0,
                          "min":0.0,
                          "max":0.0,
                          "median":0.0,
                          "mean":0.0,
                          "p25":0.0,
                          "p90":0.0,
                          "p95":0.0,
                          "p99":0.0,
                          "p99.9":0.0
                      }
                   },
                   "read_latency_statistics":{
                      "count":0,
                      "min":0.0,
                      "max":0.0,
                      "median":0.0,
                      "mean":0.0,
                      "p25":0.0,
                      "p90":0.0,
                      "p95":0.0,
                      "p99":0.0,
                      "p99.9":0.0
                   },
                   "commit_latency_statistics":{
                      "count":0,
                      "min":0.0,
                      "max":0.0,
                      "median":0.0,
                      "mean":0.0,
                      "p25":0.0,
                      "p90":0.0,
                      "p95":0.0,
                      "p99":0.0,
                      "p99.9":0.0
                   },
                   "commit_batching_window_size":{
                      "count":0,
                      "min":0.0,
                      "max":0.0,
                      "median":0.0,
                      "mean":0.0,
                      "p25":0.0,
                      "p90":0.0,
                      "p95":0.0,
                      "p99":0.0,
                      "p99.9":0.0
                   },
                   "grv_latency_bands":{ // How many GRV requests belong to the latency (in seconds) band (e.g., How many requests belong to [0.01,0.1] latency band). The key is the upper bound of the band and the lower bound is the next smallest band (or 0, if none). Example: {0.01: 27, 0.1: 18, 1: 1, inf: 98,filtered: 10}, we have 18 requests in [0.01, 0.1) band.
                      "$map_key=upperBoundOfBand": 1
                   },
                   "read_latency_bands":{
                      "$map_key=upperBoundOfBand": 1
                   },
                   "commit_latency_bands":{
                      "$map_key=upperBoundOfBand": 1
                   },
                   "busiest_read_tag":{
                      "tag": "",
                      "fractional_cost": 0.0,
                      "estimated_cost":{
                         "hz":0.0
                      }
                   },
                   "busiest_write_tag":{
                      "tag": "",
                      "fractional_cost": 0.0,
                      "estimated_cost":{
                         "hz":0.0
                      }
                   }
                }
             ],
             "command_line":"-r simulation",
             "memory":{
                "available_bytes":0, // an estimate of the process' fair share of the memory available to fdbservers
                "limit_bytes":0, // memory limit per process
                "unused_allocated_memory":0,
                "used_bytes":0, // virtual memory size of the process
                "rss_bytes":0 // resident memory size of the process
             },
             "messages":[
                {
                   "time":12345.12312,
                   "type":"x",
                   "name":{ // when not limiting
                      "$enum":[
                         "file_open_error",
                         "incorrect_cluster_file_contents",
                         "trace_log_file_write_error",
                         "trace_log_could_not_create_file",
                         "trace_log_writer_thread_unresponsive",
                         "process_error",
                         "io_error",
                         "io_timeout",
                         "platform_error",
                         "storage_server_lagging",
                         "(other FDB error messages)"
                      ]
                   },
                   "raw_log_message":"<stuff/>",
                   "description":"abc"
                }
             ],
             "fault_domain":"0ccb4e0fdbdb5583010f6b77d9d10ece",
             "under_maintenance":true,
             "excluded":false,
             "address":"1.2.3.4:1234",
             "disk":{
                "free_bytes":3451233456234,
                "reads":{
                   "hz":0.0,
                   "counter":0,
                   "sectors":0
                },
                "busy":0.0, // from 0.0 (idle) to 1.0 (fully busy)
                "writes":{
                   "hz":0.0,
                   "counter":0,
                   "sectors":0
                },
                "total_bytes":123412341234
             },
             "uptime_seconds":1234.2345,
             "cpu":{
                "usage_cores":0.0 // average number of logical cores utilized by the process over the recent past; value may be > 1.0
             },
             "network":{
                "current_connections":0,
                "connections_established":{
                    "hz":0.0
                },
                "connections_closed":{
                    "hz":0.0
                },
                "connection_errors":{
                    "hz":0.0
                },
                "megabits_sent":{
                   "hz":0.0
                },
                "megabits_received":{
                   "hz":0.0
                },
                "tls_policy_failures":{
                   "hz":0.0
                }
             },
             "run_loop_busy":0.2 // fraction of time the run loop was busy
          }
       },
       "logs":[
          {
             "log_interfaces":[ // this field will be absent if a value has not been explicitly set
                {
                   "id":"7f8d623d0cb9966e",
                   "healthy":true,
                   "address":"1.2.3.4:1234"
                }
             ],
             "epoch":1,
             "current":false,
             "begin_version":23,
             "end_version":112315141,
             "possibly_losing_data":true,
             "log_replication_factor":3,
             "log_write_anti_quorum":0,
             "log_fault_tolerance":2,
             "remote_log_replication_factor":3,
             "remote_log_fault_tolerance":2,
             "satellite_log_replication_factor":3,
             "satellite_log_write_anti_quorum":0,
             "satellite_log_fault_tolerance":2
          }
       ],
       "fault_tolerance":{
          "max_zone_failures_without_losing_availability":0,
          "max_zone_failures_without_losing_data":0
       },
       "qos":{
          "worst_queue_bytes_log_server":460,
          "batch_performance_limited_by":{
             "reason_server_id":"7f8d623d0cb9966e",
             "reason_id":0,
             "name":{ // when not limiting
                "$enum":[
                   "workload",
                   "storage_server_write_queue_size",
                   "storage_server_write_bandwidth_mvcc",
                   "storage_server_readable_behind",
                   "log_server_mvcc_write_bandwidth",
                   "log_server_write_queue",
                   "storage_server_min_free_space",
                   "storage_server_min_free_space_ratio",
                   "log_server_min_free_space",
                   "log_server_min_free_space_ratio",
                   "storage_server_durability_lag",
                   "storage_server_list_fetch_failed",
                   "blob_worker_lag",
                   "blob_worker_missing"
                ]
             },
             "description":"The database is not being saturated by the workload."
          },
          "performance_limited_by":{
             "reason_server_id":"7f8d623d0cb9966e",
             "reason_id":0,
             "name":{ // when not limiting
                "$enum":[
                   "workload",
                   "storage_server_write_queue_size",
                   "storage_server_write_bandwidth_mvcc",
                   "storage_server_readable_behind",
                   "log_server_mvcc_write_bandwidth",
                   "log_server_write_queue",
                   "storage_server_min_free_space",
                   "storage_server_min_free_space_ratio",
                   "log_server_min_free_space",
                   "log_server_min_free_space_ratio",
                   "storage_server_durability_lag",
                   "storage_server_list_fetch_failed",
                   "blob_worker_lag",
                   "blob_worker_missing"
                ]
             },
             "description":"The database is not being saturated by the workload."
          },
          "batch_transactions_per_second_limit":0,
          "transactions_per_second_limit":0,
          "batch_released_transactions_per_second":0,
          "released_transactions_per_second":0,
          "throttled_tags":{
             "auto" : {
                 "busy_read" : 0,
                 "busy_write" : 0,
                 "count" : 0,
                 "recommended_only":0
             },
             "manual" : {
                 "count" : 0
             }
          },
          "limiting_queue_bytes_storage_server":0,
          "worst_queue_bytes_storage_server":0,
          "limiting_data_lag_storage_server":{
             "versions":0,
             "seconds":0.0
          },
          "worst_data_lag_storage_server":{
             "versions":0,
             "seconds":0.0
          },
          "limiting_durability_lag_storage_server":{
             "versions":0,
             "seconds":0.0
          },
          "worst_durability_lag_storage_server":{
             "versions":0,
             "seconds":0.0
          }
       },
       "incompatible_connections":[
       ],
       "datacenter_lag":{
          "seconds":1.0,
          "versions":1000000
       },
       "active_tss_count":0,
       "degraded_processes":0,
       "database_available":true,
       "database_lock_state":{
          "locked":true,
          "lock_uid":"00000000000000000000000000000000" // Only present when database is locked
       },
       "generation":2,
       "latency_probe":{ // all measurements are based on running sample transactions
          "read_seconds":7, // time to perform a single read
          "immediate_priority_transaction_start_seconds":0.0, // time to start a sample transaction at system immediate priority
          "batch_priority_transaction_start_seconds":0.0, // time to start a sample transaction at batch priority
          "transaction_start_seconds":0.0, // time to start a sample transaction at normal priority
          "commit_seconds":0.02 // time to commit a sample transaction
       },
       "clients":{
          "count":1,
          "supported_versions":[
              {
                  "client_version":"3.0.0",
                  "connected_clients":[
                      {
                          "address":"127.0.0.1:9898",
                          "log_group":"default"
                      }
                  ],
                  "max_protocol_clients":[
                      {
                          "address":"127.0.0.1:9898",
                          "log_group":"default"
                      }
                  ],
                  "count" : 1,
                  "max_protocol_count" : 1,
                  "protocol_version" : "fdb00a400050001",
                  "source_version" : "9430e1127b4991cbc5ab2b17f41cfffa5de07e9d"
              }
          ]
       },
       "page_cache":{
          "log_hit_rate":0.5,
          "storage_hit_rate":0.5
       },
       "messages":[
          {
             "reasons":[
                {
                   "description":"Blah."
                }
             ],
             "unreachable_processes":[
                {
                   "address":"1.2.3.4:1234"
                }
             ],
             "name":{ // when not limiting
                "$enum":[
                   "unreachable_master_worker",
                   "unreachable_dataDistributor_worker",
                   "unreachable_ratekeeper_worker",
                   "unreadable_configuration",
                   "full_replication_timeout",
                   "client_issues",
                   "unreachable_processes",
                   "immediate_priority_transaction_start_probe_timeout",
                   "batch_priority_transaction_start_probe_timeout",
                   "transaction_start_probe_timeout",
                   "read_probe_timeout",
                   "commit_probe_timeout",
                   "storage_servers_error",
                   "status_incomplete",
                   "layer_status_incomplete",
                   "database_availability_timeout",
                   "consistencycheck_suspendkey_fetch_timeout",
                   "consistencycheck_disabled",
                   "duplicate_mutation_streams",
                   "duplicate_mutation_fetch_timeout",
                   "primary_dc_missing",
                   "fetch_primary_dc_timeout",
                   "fetch_storage_wiggler_stats_timeout",
                   "fetch_consistency_scan_info_timeout"
                ]
             },
             "issues":[
                {
                   "name":{ // when not limiting
                      "$enum":[
                         "incorrect_cluster_file_contents",
                         "trace_log_file_write_error",
                         "trace_log_could_not_create_file",
                         "trace_log_writer_thread_unresponsive"
                      ]
                   },
                   "description":"Cluster file contents do not match current cluster connection string. Verify cluster file is writable and has not been overwritten externally."
                }
             ],
             "description":"abc"
          }
       ],
       "recovery_state":{
          "seconds_since_last_recovered":1,
          "required_resolvers":1,
          "required_commit_proxies":1,
          "required_grv_proxies":1,
          "name":{ // "fully_recovered" is the healthy state; other states are normal to transition through but not to persist in
             "$enum":[
                "reading_coordinated_state",
                "locking_coordinated_state",
                "locking_old_transaction_servers",
                "reading_transaction_system_state",
                "configuration_missing",
                "configuration_never_created",
                "configuration_invalid",
                "recruiting_transaction_servers",
                "initializing_transaction_servers",
                "recovery_transaction",
                "writing_coordinated_state",
                "accepting_commits",
                "all_logs_recruited",
                "storage_recovered",
                "fully_recovered"
             ]
          },
          "required_logs":3,
          "missing_logs":"7f8d623d0cb9966e",
          "active_generations":1,
          "description":"Recovery complete."
       },
       "workload":{
          "operations":{
             "writes":{
                "hz":0.0,
                "counter":0,
                "roughness":0.0
             },
             "reads":{ // measures number of completed read requests
                "hz":0.0,
                "counter":0,
                "roughness":0.0
             },
             "read_requests":{ // measures number of incoming read requests
                "hz":0.0,
                "counter":0,
                "roughness":0.0
             },
              "low_priority_reads":{ // measures number of incoming low priority read requests
                "hz":0.0,
                "counter":0,
                "roughness":0.0
             },
             "location_requests":{ // measures number of outgoing key server location responses
                "hz":0.0,
                "counter":0,
                "roughness":0.0
             },
             "memory_errors":{ // measures number of (commit/grv)_proxy_memory_limit_exceeded errors
                "hz":0.0,
                "counter":0,
                "roughness":0.0
             }
          },
          "bytes":{ // measures number of logical bytes read/written (ignoring replication factor and overhead on disk). Perfectly spaced operations will have a roughness of 1.0. Randomly spaced (Poisson-distributed) operations will have a roughness of 2.0, with increased bunching resulting in increased values. Higher roughness can result in increased latency due to increased queuing.
             "written":{
                "hz":0.0,
                "counter":0,
                "roughness":0.0
             },
             "read":{
                "hz":0.0,
                "counter":0,
                "roughness":0.0
             }
          },
          "keys":{
             "read":{
                "hz":0.0,
                "counter":0,
                "roughness":0.0
             }
          },
          "transactions":{
             "started":{
                "hz":0.0,
                "counter":0,
                "roughness":0.0
             },
             "started_immediate_priority":{
                "hz":0.0,
                "counter":0,
                "roughness":0.0
             },
             "started_default_priority":{
                "hz":0.0,
                "counter":0,
                "roughness":0.0
             },
             "started_batch_priority":{
                "hz":0.0,
                "counter":0,
                "roughness":0.0
             },
             "conflicted":{
                "hz":0.0,
                "counter":0,
                "roughness":0.0
             },
             "rejected_for_queued_too_long":{
                "hz":0.0,
                "counter":0,
                "roughness":0.0
             },
             "committed":{
                "hz":0.0,
                "counter":0,
                "roughness":0.0
             }
          }
       },
       "cluster_controller_timestamp":1415650089,
       "protocol_version":"fdb00a400050001",
       "connection_string":"a:a@127.0.0.1:4000",
       "full_replication":true,
       "maintenance_zone":"0ccb4e0fdbdb5583010f6b77d9d10ece",
       "maintenance_seconds_remaining":1.0,
       "data_distribution_disabled_for_ss_failures":true,
       "data_distribution_disabled_for_rebalance":true,
       "data_distribution_disabled":true,
       "active_primary_dc":"pv",
       "bounce_impact":{
          "can_clean_bounce":true,
          "reason":""
       },
       "configuration":{
          "log_anti_quorum":0,
          "log_replicas":2,
          "log_replication_policy":"(zoneid^3x1)",
          "redundancy_mode":{
          "$enum":[
              "single",
              "double",
              "triple",
              "three_datacenter",
              "three_datacenter_fallback",
              "three_data_hall",
              "three_data_hall_fallback"
          ]},
          "regions":[{
          "datacenters":[{
              "id":"mr",
              "priority":1,
              "satellite":1,
              "satellite_logs":2
          }],
          "satellite_redundancy_mode":{
          "$enum":[
              "one_satellite_single",
              "one_satellite_double",
              "one_satellite_triple",
              "two_satellite_safe",
              "two_satellite_fast"
          ]},
          "satellite_log_replicas":1,
          "satellite_usable_dcs":1,
          "satellite_anti_quorum":0,
          "satellite_log_policy":"(zoneid^3x1)",
          "satellite_logs":2
          }],
          "remote_redundancy_mode":{
          "$enum":[
              "remote_default",
              "remote_single",
              "remote_double",
              "remote_triple",
              "remote_three_data_hall"
          ]},
          "remote_log_replicas":3,
          "remote_logs":5,
          "log_routers":10,
          "usable_regions":1,
          "repopulate_anti_quorum":1,
          "storage_replicas":1,
          "resolvers":1, // this field will be absent if a value has not been explicitly set
          "storage_replication_policy":"(zoneid^3x1)",
          "logs":2, // this field will be absent if a value has not been explicitly set
          "log_version":2,
          "log_engine":{
          "$enum":[
              "ssd",
              "ssd-1",
              "ssd-2",
              "ssd-redwood-1",
              "ssd-rocksdb-v1",
              "ssd-sharded-rocksdb",
              "memory",
              "memory-1",
              "memory-2",
              "memory-radixtree-beta"
          ]},
          "log_spill":1,
          "storage_engine":{
          "$enum":[
              "ssd",
              "ssd-1",
              "ssd-2",
              "ssd-redwood-1",
              "ssd-rocksdb-v1",
              "ssd-sharded-rocksdb",
              "memory",
              "memory-1",
              "memory-2",
              "memory-radixtree-beta"
          ]},
          "tss_count":1,
          "tss_storage_engine":{
          "$enum":[
              "ssd",
              "ssd-1",
              "ssd-2",
              "ssd-redwood-1",
              "ssd-rocksdb-v1",
              "ssd-sharded-rocksdb",
              "memory",
              "memory-1",
              "memory-2",
              "memory-radixtree-beta"
          ]},
          "coordinators_count":1,
          "excluded_servers":[
             {
                "address":"10.0.4.1",
                "locality":"locality_processid:e9816ca4a89ff64ddb7ba2a5ec10b75b"
             }
          ],
          "auto_commit_proxies":3,
          "auto_grv_proxies":1,
          "auto_resolvers":1,
          "auto_logs":3,
          "commit_proxies":5, // this field will be absent if a value has not been explicitly set
          "grv_proxies":1, // this field will be absent if a value has not been explicitly set
          "proxies":6, // this field will be absent if a value has not been explicitly set
          "backup_worker_enabled":1,
          "perpetual_storage_wiggle": 0,
          "perpetual_storage_wiggle_locality":"0",
          "perpetual_storage_wiggle_engine":{
          "$enum":[
              "ssd",
              "ssd-1",
              "ssd-2",
              "ssd-redwood-1",
              "ssd-rocksdb-v1",
              "ssd-sharded-rocksdb",
              "memory",
              "memory-1",
              "memory-2",
              "memory-radixtree-beta",
              "none"
          ]},
          "storage_migration_type":{
          "$enum":[
              "disabled",
              "gradual",
              "aggressive"
          ]},
          "tenant_mode": {
              "$enum":[
              "disabled",
              "optional_experimental",
              "required_experimental"
          ]},
          "encryption_at_rest_mode": {
              "$enum":[
              "disabled",
              "aes_256_ctr"
          ]}
       },
       "data":{
          "least_operating_space_bytes_log_server":0,
          "average_partition_size_bytes":0,
          "state":{
             "healthy":true,
             "min_replicas_remaining":0,
             "name":{ // when not limiting
                "$enum":[
                   "initializing",
                   "missing_data",
                   "healing",
                   "optimizing_team_collections",
                   "healthy_populating_region",
                   "healthy_repartitioning",
                   "healthy_removing_server",
                   "healthy_rebalancing",
                   "healthy"
                ]
             },
             "description":""
          },
          "least_operating_space_ratio_storage_server":0.1,
          "max_machine_failures_without_losing_availability":0,
          "total_disk_used_bytes":0,
          "total_kv_size_bytes":0, // estimated
          "system_kv_size_bytes":0, // estimated
          "partitions_count":2,
          "moving_data":{
             "total_written_bytes":0, // reset whenever data distributor is re-recruited
             "in_flight_bytes":0, // number of bytes currently being moved between storage servers
             "in_queue_bytes":0, // number of bytes in the data distributor queue that should be moved (but are not yet being transferred between storage servers)
             "highest_priority":0
          },
          "team_trackers":[
             {
                 "primary":true,
                 "in_flight_bytes":0,
                 "unhealthy_servers":0,
                 "state":{
                     "healthy":true,
                     "min_replicas_remaining":0,
                     "name":{ // when not limiting
                        "$enum":[
                           "initializing",
                           "missing_data",
                           "healing",
                           "optimizing_team_collections",
                           "healthy_populating_region",
                           "healthy_repartitioning",
                           "healthy_removing_server",
                           "healthy_rebalancing",
                           "healthy"
                        ]
                     },
                     "description":""
                 }
             }
          ],
          "least_operating_space_bytes_storage_server":0,
          "max_machine_failures_without_losing_data":0
       },
       "machines":{
          "$map_key=machineid":{
             "network":{
                "megabits_sent":{
                   "hz":0.0
                },
                "megabits_received":{
                   "hz":0.0
                },
                "tcp_segments_retransmitted":{
                   "hz":0.0
                }
             },
             "memory":{
                "free_bytes":0, // an estimate of how many bytes are free to allocate to fdbservers without swapping
                "committed_bytes":0, // an estimate of the number of bytes of memory on the machine that are not free for allocation
                "total_bytes":0 // an estimate of total physical RAM
             },
             "contributing_workers":4,
             "datacenter_id":"6344abf1813eb05b",
             "excluded":false,
             "address":"1.2.3.4",
             "machine_id":"6344abf1813eb05b",
             "locality":{ // This will contain any locality fields that are provided on the command line
                 "$map_key=localityName":"value"
             },
             "cpu":{
                "logical_core_utilization":0.4 // computed as cpu_seconds / elapsed_seconds; value may be capped at 0.5 due to hyper-threading
             }
          }
       },
       "metacluster" : {
          "cluster_type" : "management",         // management, data, or standalone
          "metacluster_name" : "metacluster1",
          "metacluster_id" : 12345,
          "data_cluster_name" : "data_cluster1", // data cluster only
          "data_cluster_id" : 12346,             // data cluster only
          "num_data_clusters": 10                // management cluster only
       },
       "tenants" : {
          "num_tenants" : 1, // on data cluster, local count; on management cluster, total metacluster count
          "num_tenant_groups" : 10,
          "tenant_group_capacity" : 20,
       },
       "idempotency_ids" : {
          "size_bytes" : 0, // An estimate of the current number of bytes used in the database to store idempotency ids.
          "expired_version" : 0, // The commit status of a transaction whose commit version could be <= expired_version can no longer be determined.
          "expired_age" : 0, // The age in seconds of expired_version.
          "oldest_id_version" : 0, // The version of the oldest idempotency id still stored in the database.
          "oldest_id_age" : 0 // The age in seconds of the oldest_id_version.
       },
       "version_epoch":{
          "enabled": true,
          "epoch": 0 // The version epoch, as an offset from the Unix epoch. This field will be excluded if enabled is false.
       }
    },
    "client":{
       "coordinators":{
          "coordinators":[
             {
                "reachable":true,
                "address":"127.0.0.1:4701",
                "protocol":"0fdb00b070010001"
             }
          ],
          "quorum_reachable":true
       },
       "database_status":{
          "available":true,
          "healthy":true
       },
       "messages":[
          {
             "name":{ // when not limiting
                "$enum":[
                   "inconsistent_cluster_file",
                   "unreachable_cluster_controller",
                   "no_cluster_controller",
                   "status_incomplete_client",
                   "status_incomplete_coordinators",
                   "status_incomplete_error",
                   "status_incomplete_timeout",
                   "status_incomplete_cluster",
                   "quorum_not_reachable"
                ]
             },
             "description":"The cluster file is not up to date."
          }
       ],
       "timestamp":1415650089,
       "cluster_file":{
          "path":"/etc/foundationdb/fdb.cluster",
          "up_to_date":true
       }
    }

### Message components

Several fields in the JSON object may contain messages in the format:

    "messages": [
      {
        "name": <name_string>,
        "description": <description_string>
      }
    ]

Each message is an Object having at least a `"name"` field. The `"description"` is present only in some messages. Other fields may be present based on specific message instance details. The possible name and description values of a message found at a given location in the JSON object are described in the tables below.

JSON Path | Name | Description
--- | --- | ---

client.messages

inconsistent_cluster_file

Cluster file is not up to date. It contains the connection string ‘<value>’. The current connection string is ‘<value>’. This must mean that file permissions or other platform issues have prevented the file from being updated. To change coordinators without manual intervention, the cluster file and its containing folder must be writable by all servers and clients. If a majority of the coordinators referenced by the old connection string are lost, the database will stop working until the correct cluster file is distributed to all processes.

client.messages | no_cluster_controller | Unable to locate a cluster controller within 2 seconds. Check that there are server processes running.
client.messages | quorum_not_reachable | Unable to reach a quorum of coordinators.
client.messages | server_overloaded | Server is under too much load and cannot respond.
client.messages | status_incomplete_client | Could not retrieve client status information.
client.messages | status_incomplete_cluster | Could not retrieve cluster status information.
client.messages | status_incomplete_coordinators | Could not fetch coordinator info.
client.messages | status_incomplete_error | Cluster encountered an error fetching status.
client.messages | status_incomplete_timeout | Timed out fetching cluster status.
client.messages | unreachable_cluster_controller | No response received from the cluster controller.
cluster.messages | client_issues | Some clients of this cluster have issues.
cluster.messages | commit_timeout | Unable to commit after __ seconds.
cluster.messages | read_timeout | Unable to read after __ seconds.
cluster.messages | status_incomplete | Unable to retrieve all status information.
cluster.messages | storage_servers_error | Timed out trying to retrieve storage servers.
cluster.messages | log_servers_error | Timed out trying to retrieve log servers.
cluster.messages | transaction_start_timeout | Unable to start transaction after __ seconds.
cluster.messages | unreachable_master_worker | Unable to locate the master worker.
cluster.messages | unreachable_dataDistributor_worker | Unable to locate the data distributor worker.
cluster.messages | unreachable_ratekeeper_worker | Unable to locate the ratekeeper worker.
cluster.messages | unreachable_processes | The cluster has some unreachable processes.
cluster.messages | unreadable_configuration | Unable to read database configuration.
cluster.messages | layer_status_incomplete | Some or all of the layers subdocument could not be read.
cluster.messages | primary_dc_missing | Unable to determine primary datacenter.
cluster.messages | fetch_primary_dc_timeout | Fetching primary DC timed out.
cluster.processes.<process>.messages | file_open_error | Unable to open ‘<file>’ (<os_error>).
cluster.processes.<process>.messages | incorrect_cluster_file_contents | Cluster file contents do not match current cluster connection string. Verify cluster file is writable and has not been overwritten externally.
cluster.processes.<process>.messages | io_error | <error> occured in <subsystem>
cluster.processes.<process>.messages | platform_error | <error> occured in <subsystem>
cluster.processes.<process>.messages | process_error | <error> occured in <subsystem>

The JSON path `cluster.recovery_state`, when it exists, is an Object containing at least `"name"` and `"description"`. The possible values for those fields are in the following table:

Name | Description
--- | ---
reading_coordinated_state | Requesting information from coordination servers. Verify that a majority of coordination server processes are active.
locking_coordinated_state | Locking coordination state. Verify that a majority of coordination server processes are active.
reading_transaction_system_state | Recovering transaction server state. Verify that the transaction server processes are active.
configuration_missing | There appears to be a database, but its configuration does not appear to be initialized.
configuration_never_created | The coordinator(s) have no record of this database. Either the coordinator addresses are incorrect, the coordination state on those machines is missing, or no database has been created.
configuration_invalid | The database configuration is invalid. Set a new, valid configuration to recover the database.
recruiting_transaction_servers | Recruiting new transaction servers.
initializing_transaction_servers | Initializing new transaction servers and recovering transaction logs.
recovery_transaction Performing | recovery transaction.
writing_coordinated_state | Writing coordinated state. Verify that a majority of coordination server processes are active.
fully_recovered | Recovery complete.

The JSON path `cluster.qos.performance_limited_by`, when it exists, is an Object containing at least `"name"` and `"description"`. The possible values for those fields are in the following table:

Name | Description
--- | ---
workload | The database is not being saturated by the workload.
storage_server_write_queue_size | Storage server performance (storage queue).
storage_server_write_bandwidth_mvcc | Storage server MVCC memory.
storage_server_readable_behind | Storage server version falling behind.
log_server_mvcc_write_bandwidth | Log server MVCC memory.
log_server_write_queue | Storage server performance (log queue).
min_free_space | Running out of space (approaching 100MB limit).
min_free_space_ratio | Running out of space (approaching 5% limit).
log_server_min_free_space | Log server running out of space (approaching 100MB limit).
log_server_min_free_space_ratio | Log server running out of space (approaching 5% limit).
storage_server_durability_lag | Storage server durable version falling behind.
storage_server_list_fetch_failed | Unable to fetch storage server list.
blob_worker_lag | Blob worker granule version falling behind.
blob_worker_missing | No blob workers are reporting metrics.

The JSON path `cluster.qos.throttled_tags`, when it exists, is an Object containing `"auto"` , `"manual"` and `"recommended"`. The possible fields for those object are in the following table:

Name | Description
--- | ---
count | How many tags are throttled
busy_read | How many tags are throttled because of busy read
busy_write | How many tags are throttled because of busy write