Master MongoDB Config: System Log, Network, Security & More

MongoDB Configuration File Explanation

System Log Configuration

systemLog:
  verbosity: <int>
  quiet: <boolean>
  traceAllExceptions: <boolean>
  syslogFacility: <string>
  path: <string>
  logAppend: <boolean>
  logRotate: <string>
  destination: <string>
  timeStampFormat: <string>
  component:
  accessControl:
    verbosity: <int>
  command:
    verbosity: <int>

verbosity : Log level, default 0, range 1‑5.

quiet : Suppress log output; not recommended for production.

traceAllExceptions : Print detailed exception information for troubleshooting.

syslogFacility : Default "user"; logs are sent to syslog facility; requires --syslog option.

path : Specifies log file location.

logAppend : When true, logs are appended after restart; default false creates new file each start.

logRotate : Log rotation method, default "rename". Can set "reopen" with logAppend=true.

destination : Output method, file or syslog.

timeStampFormat : Timestamp format, default local (iso8601-local); options iso8601-utc, ctime.

Process Management

processManagement:
  fork: <boolean>
  pidFilePath: <string>

fork : Run as daemon.

pidFilePath : Location of PID file.

Network Options

net:
  port: <int>
  bindIp: <string>
  maxIncomingConnections: <int>
  wireObjectCheck: <boolean>
  ipv6: <boolean>
  unixDomainSocket:
    enabled: <boolean>
    pathPrefix: <string>
    filePermissions: <int>
  http:
    enabled: <boolean>
    JSONPEnabled: <boolean>
    RESTInterfaceEnabled: <boolean>
  ssl:
    sslOnNormalPorts: <boolean> # deprecated since 2.6
    mode: <string>
    PEMKeyFile: <string>
    PEMKeyPassword: <string>
    clusterFile: <string>
    clusterPassword: <string>
    CAFile: <string>
    CRLFile: <string>
    allowConnectionsWithoutCertificates: <boolean>
    allowInvalidCertificates: <boolean>
    allowInvalidHostnames: <boolean>
    disabledProtocols: <string>
    FIPSMode: <boolean>
    compression:
    compressors: <string>

net.port : Listening port.

net.bindIp : IP address to bind.

net.maxIncomingConnections : Maximum concurrent connections, default 65535.

net.wireObjectCheck : Validate incoming BSON, default true.

net.ipv6 : Enable IPv6, default false.

net.unixDomainSocket.enabled : Enable Unix domain socket, default true.

net.unixDomainSocket.pathPrefix : Socket file path, default /tmp.

net.unixDomainSocket.filePermissions : Permissions for socket file, default 0700.

net.http.enabled : HTTP interface, default false (deprecated since 3.2).

net.http.JSONPEnabled and net.http.RESTInterfaceEnabled : Deprecated JSONP and REST API options.

net.ssl : SSL configuration parameters.

net.compression.compressors : Enable network compression.

Security Settings

security:
  keyFile: <string>
  clusterAuthMode: <string>
  authorization: <string>
  transitionToAuth: <boolean>
  javascriptEnabled: <boolean>
  redactClientLogData: <boolean>
  sasl:
    hostName: <string>
    serviceName: <string>
    saslauthdSocketPath: <string>
  enableEncryption: <boolean>
  encryptionCipherMode: <string>
  encryptionKeyFile: <string>
  kmip:
    keyIdentifier: <string>
    rotateMasterKey: <boolean>
    serverName: <string>
    port: <string>
    clientCertificateFile: <string>
    clientCertificatePassword: <string>
    serverCAFile: <string>
  ldap:
    servers: <string>
    bind:
      method: <string>
      saslMechanism: <string>
      queryUser: <string>
      queryPassword: <string>
      useOSDefaults: <boolean>
    transportSecurity: <string>
    timeoutMS: <int>
    userToDNMapping: <string>
    authz:
      queryTemplate: <string>

security.authorization : Default "disable"; enables role‑based access control when set.

Storage Configuration

storage:
  dbPath: <string>
  indexBuildRetry: <boolean>
  repairPath: <string>
  journal:
    enabled: <boolean>
    commitIntervalMs: <num>
  directoryPerDB: <boolean>
  syncPeriodSecs: <int>
  engine: <string>
  mmapv1:
    preallocDataFiles: <boolean>
    nsSize: <int>
    quota:
      enforced: <boolean>
    maxFilesPerDB: <int>
    smallFiles: <boolean>
    journal:
      debugFlags: <int>
      commitIntervalMs: <num>
  wiredTiger:
    engineConfig:
      cacheSizeGB: <number>
      journalCompressor: <string>
    directoryForIndexes: <boolean>
    collectionConfig:
      blockCompressor: <string>
    indexConfig:
      prefixCompression: <boolean>
  inMemory:
    engineConfig:
      inMemorySizeGB: <number>

storage.dbPath : Path for data files.

storage.indexBuildRetry : Rebuild incomplete indexes on startup; default true.

storage.repairPath : Temporary path for --repair; removed after use.

storage.journal.enabled : Enable journaling; default true on 64‑bit.

storage.journal.commitIntervalMs : Max time between journal writes, default 100 ms.

storage.directoryPerDB : Store each database in its own directory when true.

storage.syncPeriodSecs : Interval for syncing data to disk; default 60 s, 0 disables syncing.

storage.engine : Storage engine, default "wiredTiger".

storage.mmapv1.preallocDataFiles : Pre‑allocate data files; default true.

storage.mmapv1.nsSize : Namespace file size, default 16 MB.

storage.mmapv1.quota.enforced : Enforce per‑database file count limit; default false.

storage.mmapv1.quota.maxFilesPerDB : Max data files per database; default 8.

storage.mmapv1.smallFiles : Use smaller default file size; default false.

storage.wiredTiger.engineConfig.cacheSizeGB : Maximum internal cache size; up to half of RAM minus 1 GB.

storage.wiredTiger.engineConfig.journalCompressor : Compression for WiredTiger journal (none, snappy, zlib).

storage.wiredTiger.directoryForIndexes : Store indexes in a separate directory when true.

storage.wiredTiger.collectionConfig.blockCompressor : Data compression format (none, snappy, zlib).

storage.wiredTiger.indexConfig.prefixCompression : Enable prefix compression for indexes; default true.

storage.inMemory.engineConfig.inMemorySizeGB : Max memory for in‑memory engine; default half of RAM minus 1 GB.

Slow Query Profiling

operationProfiling:
  slowOpThresholdMs: <int>
  mode: <string>

operationProfiling.slowOpThresholdMs : Threshold for slow operations, default 100 ms.

operationProfiling.mode : Profiling mode; "slowOp" records slow queries, "all" records all operations.

Replication Settings

replication:
  oplogSizeMB: <int>
  replSetName: <string>
  secondaryIndexPrefetch: <string>
  enableMajorityReadConcern: <boolean>

replication.oplogSizeMB : Maximum size of the oplog; default about 5 % of disk.

replication.replSetName : Name of the replica set.

replication.secondaryIndexPrefetch : For mmapv1 engine, default "all"; preloads indexes before applying oplog.

replication.enableMajorityReadConcern : Enable majority read concern; default false.

Sharding Configuration

sharding:
  clusterRole: <string>
  archiveMovedChunks: <boolean>

sharding.clusterRole : Role of the node, e.g., "configsvr" or "shardsvr".

sharding.archiveMovedChunks : Whether to archive chunks moved during migration; default false.

Mongos Parameters

mongos:
  replication:
    localPingThresholdMs: <int>
  sharding:
    configDB: <string>

mongos.replication.localPingThresholdMs : Default 15 ms; ping value updated every 10 s to route requests to low‑latency secondaries.

mongos.sharding.configDB : List of config servers for the cluster.