`mongod`¶

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Synopsis
Options

Synopsis¶

mongod is the primary daemon process for the MongoDB system. It handles data requests, manages data access, and performs background management operations.

This document provides a complete overview of all command line options for mongod. These command line options are primarily useful for testing: In common operation, use the configuration file options to control the behavior of your database.

Options¶

Core Options¶

mongod¶

--help, -h¶: Returns information on the options and use of mongod.

--version¶: Returns the mongod release number.

--config <filename>, -f <filename>¶

Specifies a configuration file for runtime configuration options. The configuration file is the preferred method for runtime configuration of mongod. The options are equivalent to the command-line configuration options. See Configuration File Options for more information.

Ensure the configuration file uses ASCII encoding. The mongod instance does not support configuration files with non-ASCII encoding, including UTF-8.

--verbose, -v¶: Increases the amount of internal reporting returned on standard output or in log files. Increase the verbosity with the -v form by including the option multiple times, (e.g. -vvvvv.)

--quiet¶

Runs the mongod in a quiet mode that attempts to limit the amount of output.

This option suppresses:

output from database commands
replication activity
connection accepted events
connection closed events

--port <port>¶

Default: 27017

Specifies the TCP port on which the MongoDB instance listens for client connections.

--bind_ip <ip address>¶

Default: All interfaces.

Changed in version 2.6.0: The deb and rpm packages include a default configuration file (/etc/mongod.conf) that sets --bind_ip to 127.0.0.1.

Specifies the IP address that mongod binds to in order to listen for connections from applications. You may attach mongod to any interface. When attaching mongod to a publicly accessible interface, ensure that you have implemented proper authentication and firewall restrictions to protect the integrity of your database.

--ipv6¶: Enables IPv6 support and allows the mongod to connect to the MongoDB instance using an IPv6 network. All MongoDB programs and processes disable IPv6 support by default.

--maxConns <number>¶

The maximum number of simultaneous connections that mongod will accept. This setting has no effect if it is higher than your operating system’s configured maximum connection tracking threshold.

Do not assign too low of a value to this option, or you will encounter errors during normal application operation.

Note

Changed in version 2.6: MongoDB removed the upward limit on the maxIncomingConnections setting.

--logpath <path>¶

Sends all diagnostic logging information to a log file instead of to standard output or to the host’s syslog system. MongoDB creates the log file at the path you specify.

By default, MongoDB will move any existing log file rather than overwrite it. To instead append to the log file, set the --logappend option.

--syslog¶

Sends all logging output to the host’s syslog system rather than to standard output or to a log file. , as with --logpath.

The --syslog option is not supported on Windows.

--syslogFacility <string>¶

Default: user

Specifies the facility level used when logging messages to syslog. The value you specify must be supported by your operating system’s implementation of syslog. To use this option, you must enable the --syslog option.

--logappend¶: Appends new entries to the end of the existing log file when the mongod instance restarts. Without this option, mongod will back up the existing log and create a new file.

--logRotate <string>¶

Default: rename

New in version 3.0.0.

Determines the behavior for the logRotate command. Specify either rename or reopen:

rename renames the log file.
reopen closes and reopens the log file following the typical Linux/Unix log rotate behavior. Use reopen when using the Linux/Unix logrotate utility to avoid log loss.

If you specify reopen, you must also use --logappend.

--timeStampFormat <string>¶

Default: iso8601-local

The time format for timestamps in log messages. Specify one of the following values:

Value	Description
`ctime`	Displays timestamps as `Wed Dec 31 18:17:54.811`.
`iso8601-utc`	Displays timestamps in Coordinated Universal Time (UTC) in the ISO-8601 format. For example, for New York at the start of the Epoch: `1970-01-01T00:00:00.000Z`
`iso8601-local`	Displays timestamps in local time in the ISO-8601 format. For example, for New York at the start of the Epoch: `1969-12-31T19:00:00.000-0500`

--diaglog <value>¶

Default: 0

Deprecated since version 2.6.

--diaglog is for internal use and not intended for most users.

Creates a very verbose diagnostic log for troubleshooting and recording various errors. MongoDB writes these log files in the dbPath directory in a series of files that begin with the string diaglog and end with the initiation time of the logging as a hex string.

The specified value configures the level of verbosity:

Value	Setting
0	Off. No logging.
1	Log write operations.
2	Log read operations.
3	Log both read and write operations.
7	Log write and some read operations.

You can use the mongosniff tool to replay this output for investigation. Given a typical diaglog file located at /data/db/diaglog.4f76a58c, you might use a command in the following form to read these files:

mongosniff --source DIAGLOG /data/db/diaglog.4f76a58c

Warning

Setting the diagnostic level to 0 will cause mongod to stop writing data to the diagnostic log file. However, the mongod instance will continue to keep the file open, even if it is no longer writing data to the file. If you want to rename, move, or delete the diagnostic log you must cleanly shut down the mongod instance before doing so.

--traceExceptions¶: For internal diagnostic use only.

--pidfilepath <path>¶: Specifies a file location to hold the process ID of the mongod process where mongod will write its PID. This is useful for tracking the mongod process in combination with the --fork option. Without a specified --pidfilepath option, the process creates no PID file.

--keyFile <file>¶: Specifies the path to a key file that stores the shared secret that MongoDB instances use to authenticate to each other in a sharded cluster or replica set. --keyFile implies --auth. See Internal Authentication for more information.

--setParameter <options>¶: Specifies one of the MongoDB parameters described in MongoDB Server Parameters. You can specify multiple setParameter fields.

--httpinterface¶

Deprecated since version 3.2: HTTP interface for MongoDB

Enables the HTTP interface. Enabling the interface can increase network exposure.

Leave the HTTP interface disabled for production deployments. If you do enable this interface, you should only allow trusted clients to access this port. See Firewalls.

Note

While MongoDB Enterprise does support Kerberos authentication, Kerberos is not supported in HTTP status interface in any version of MongoDB.

New in version 2.6.

--nounixsocket¶

Disables listening on the UNIX domain socket. --nounixsocket applies only to Unix-based systems.

The mongod process always listens on the UNIX socket unless one of the following is true:

--nounixsocket is set
net.bindIp is not set
net.bindIp does not specify 127.0.0.1

New in version 2.6: mongod installed from official .deb and .rpm packages have the bind_ip configuration set to 127.0.0.1 by default.

--unixSocketPrefix <path>¶

Default: /tmp

The path for the UNIX socket. --unixSocketPrefix applies only to Unix-based systems.

If this option has no value, the mongod process creates a socket with /tmp as a prefix. MongoDB creates and listens on a UNIX socket unless one of the following is true:

net.unixDomainSocket.enabled is false
--nounixsocket is set
net.bindIp is not set
net.bindIp does not specify 127.0.0.1

--filePermissions <path>¶

Default: 0700

Sets the permission for the UNIX domain socket file.

--filePermissions applies only to Unix-based systems.

--fork¶: Enables a daemon mode that runs the mongod process in the background. By default mongod does not run as a daemon: typically you will run mongod as a daemon, either by using --fork or by using a controlling process that handles the daemonization process (e.g. as with upstart and systemd).

--auth¶

Enables authorization to control user’s access to database resources and operations. When authorization is enabled, MongoDB requires all clients to authenticate themselves first in order to determine the access for the client.

Configure users via the mongo shell. If no users exist, the localhost interface will continue to have access to the database until you create the first user.

See Security for more information.

--noauth¶: Disables authentication. Currently the default. Exists for future compatibility and clarity.

--jsonp¶: Permits JSONP access via an HTTP interface. Enabling the interface can increase network exposure. The --jsonp option enables the HTTP interface, even if the HTTP interface option is disabled.

Deprecated since version 3.2: HTTP interface for MongoDB

--rest¶: Enables the simple REST API. Enabling the REST API enables the HTTP interface, even if the HTTP interface option is disabled, and as a result can increase network exposure.

Deprecated since version 3.2: HTTP interface for MongoDB

--slowms <integer>¶

Default: 100

The threshold in milliseconds at which the database profiler considers a query slow. MongoDB records all slow queries to the log, even when the database profiler is off. When the profiler is on, it writes to the system.profile collection. See the profile command for more information on the database profiler.

--profile <level>¶

Default: 0

Changes the level of database profiling, which inserts information about operation performance into the system.profile collection. Specify one of the following levels:

Level	Setting
0	Off. No profiling.
1	On. Only includes slow operations.
2	On. Includes all operations.

Database profiling can impact database performance. Enable this option only after careful consideration.

--cpu¶: Forces the mongod process to report the percentage of CPU time in write lock, every four seconds.

--sysinfo¶: Returns diagnostic system information and then exits. The information provides the page size, the number of physical pages, and the number of available physical pages.

--noscripting¶: Disables the scripting engine.

--notablescan¶: Forbids operations that require a table scan. See notablescan for additional information.

--shutdown¶

The --shutdown option cleanly and safely terminates the mongod process. When invoking mongod with this option you must set the --dbpath option either directly or by way of the configuration file and the --config option.

The --shutdown option is available only on Linux systems.

Storage Options¶

--storageEngine string¶

Default: wiredTiger

New in version 3.0.

Changed in version 3.2: Starting in MongoDB 3.2, wiredTiger is the default.

Specifies the storage engine for the mongod database. Available values include:

Value	Description
`mmapv1`	To specify the MMAPv1 Storage Engine.
`wiredTiger`	To specify the WiredTiger Storage Engine.
`inMemory`	To specify the In-Memory Storage Engine. The in-memory storage engine is currently in beta. Do not use in production. New in version 3.2: Available in MongoDB Enterprise only.

If you attempt to start a mongod with a --dbpath that contains data files produced by a storage engine other than the one specified by --storageEngine, mongod will refuse to start.

--dbpath <path>¶

Default: /data/db on Linux and OS X, \data\db on Windows

The directory where the mongod instance stores its data.

If you installed MongoDB using a package management system, check the /etc/mongod.conf file provided by your packages to see the directory is specified.

Changed in version 3.0: The files in --dbpath must correspond to the storage engine specified in --storageEngine. If the data files do not correspond to --storageEngine, mongod will refuse to start.

--directoryperdb¶

Uses a separate directory to store data for each database. The directories are under the --dbpath directory, and each subdirectory name corresponds to the database name.

Changed in version 3.0: To change the --directoryperdb option for existing deployments, you must restart the mongod instances with the new --directoryperdb value and a new data directory (--dbpath <new path>), and then repopulate the data.

For standalone instances, you can use mongodump on the existing instance, stop the instance, restart with the new --directoryperdb value and a new data directory, and use mongorestore to populate the new data directory.
For replica sets, you can update in a rolling manner by stopping a secondary member, restart with the new --directoryperdb value and a new data directory, and use initial sync to populate the new data directory. To update all members, start with the secondary members first. Then step down the primary, and update the stepped-down member.

--noprealloc¶: Deprecated since version 2.6.

Disables the preallocation of data files. Currently the default. Exists for future compatibility and clarity.

--nssize <value>¶

Default: 16

Specifies the default size for namespace files, which are files that end in .ns. Each collection and index counts as a namespace.

Use this setting to control size for newly created namespace files. This option has no impact on existing files. The maximum size for a namespace file is 2047 megabytes. The default value of 16 megabytes provides for approximately 24,000 namespaces.

--quota¶: Enables a maximum limit for the number data files each database can have. When running with the --quota option, MongoDB has a maximum of 8 data files per database. Adjust the quota with --quotaFiles.

--quotaFiles <number>¶

Default: 8

Modifies the limit on the number of data files per database. --quotaFiles option requires that you set --quota.

--smallfiles¶

Sets MongoDB to use a smaller default file size. The --smallfiles option reduces the initial size for data files and limits the maximum size to 512 megabytes. --smallfiles also reduces the size of each journal file from 1 gigabyte to 128 megabytes. Use --smallfiles if you have a large number of databases that each holds a small quantity of data.

The --smallfiles option can lead the mongod instance to create a large number of files, which can affect performance for larger databases.

--syncdelay <value>¶

Default: 60

Controls how much time can pass before MongoDB flushes data to the data files via an fsync operation.

Do not set this value on production systems. In almost every situation, you should use the default setting.

Warning

If you set --syncdelay to 0, MongoDB will not sync the memory mapped files to disk.

The mongod process writes data very quickly to the journal and lazily to the data files. --syncdelay has no effect on the journal files or journaling.

The serverStatus command reports the background flush thread’s status via the backgroundFlushing field.

--upgrade¶

Upgrades the on-disk data format of the files specified by the --dbpath to the latest version, if needed.

This option only affects the operation of the mongod if the data files are in an old format.

In most cases you should not set this value, so you can exercise the most control over your upgrade process. See the MongoDB release notes (on the download page) for more information about the upgrade process.

--repair¶

Runs a repair routine on all databases. This is equivalent to shutting down and running the repairDatabase database command on all databases.

Warning

During normal operations, only use the repairDatabase command and wrappers including db.repairDatabase() in the mongo shell and mongod --repair, to compact database files and/or reclaim disk space. Be aware that these operations remove and do not save any corrupt data during the repair process.

If you are trying to repair a replica set member, and you have access to an intact copy of your data (e.g. a recent backup or an intact member of the replica set), you should restore from that intact copy, and not use repairDatabase.

When using journaling, there is almost never any need to run repairDatabase. In the event of an unclean shutdown, the server will be able to restore the data files to a pristine state automatically.

Changed in version 2.1.2.

If you run the repair option and have data in a journal file, the mongod instance refuses to start. In these cases you should start the mongod without the --repair option, which allows the mongod to recover data from the journal. This completes more quickly and is more likely to produce valid data files. To continue the repair operation despite the journal files, shut down the mongod cleanly and restart with the --repair option.

The --repair option copies data from the source data files into new data files in the repairPath and then replaces the original data files with the repaired data files.

--repairpath <path>¶

Default: A _tmp directory within the path specified by the dbPath option.

Specifies a working directory that MongoDB will use during the --repair operation. After --repair completes, the data files in option:–dbpath and the --repairpath directory is empty.

The --repairpath must be within the dbPath. You can specify a symlink to --repairpath to use a path on a different file system.

--journal¶: Enables the durability journal to ensure data files remain valid and recoverable. This option applies only when you specify the --dbpath option. The mongod enables journaling by default on 64-bit builds of versions after 2.0.

--nojournal¶: Disables the durability journaling. The mongod instance enables journaling by default in 64-bit versions after v2.0.

--journalOptions <arguments>¶: Provides functionality for testing. Not for general use, and will affect data file integrity in the case of abnormal system shutdown.

--journalCommitInterval <value>¶

Default: 100 or 30

Changed in version 3.2.

The maximum amount of time in milliseconds that the mongod process allows between journal operations. Values can range from 1 to 500 milliseconds. Lower values increase the durability of the journal, at the expense of disk performance. The default journal commit interval is 100 milliseconds.

On MMAPv1, if the journal is on a different block device (e.g. physical volume, RAID device, or LVM volume) than the data files, the default journal commit interval is 30 milliseconds. Additionally, on MMAPv1, when a write operation with j:true is pending, mongod will reduce commitIntervalMs to a third of the set value.

On WiredTiger, the default journal commit interval is 100 milliseconds. Additionally, a write with j:true will cause an immediate sync of the journal.

WiredTiger Options¶

--wiredTigerCacheSizeGB number¶

New in version 3.0.

Defines the maximum size of the cache that WiredTiger will use for all data.

With WiredTiger, MongoDB utilizes both the WiredTiger cache and the filesystem cache.

Changed in version 3.2: Starting in MongoDB 3.2, the WiredTiger cache, by default, will use the larger of either:

60% of RAM minus 1 GB, or
1 GB.

For systems with up to 10 GB of RAM, the new default setting is less than or equal to the 3.0 default setting (For MongoDB 3.0, the WiredTiger cache uses either 1 GB or half of the installed physical RAM, whichever is larger).

For systems with more than 10 GB of RAM, the new default setting is greater than the 3.0 setting.

Via the filesystem cache, MongoDB automatically uses all free memory that is not used by the WiredTiger cache or by other processes. Data in the filesystem cache is compressed.

Avoid increasing the WiredTiger cache size above its default value.

Note

The --wiredTigerCacheSizeGB only limits the size of the WiredTiger cache, not the total amount of memory used by mongod. The WiredTiger cache is only one component of the RAM used by MongoDB. MongoDB also automatically uses all free memory on the machine via the filesystem cache (data in the filesystem cache is compressed).

In addition, the operating system will use any free RAM to buffer filesystem blocks.

To accommodate the additional consumers of RAM, you may have to decrease WiredTiger cache size.

The default WiredTiger cache size value assumes that there is a single mongod instance per node. If a single node contains multiple instances, then you should decrease the setting to accommodate the other mongod instances.

If you run mongod in a container (e.g. lxc, cgroups, Docker, etc.) that does not have access to all of the RAM available in a system, you must set --wiredTigerCacheSizeGB to a value less than the amount of RAM available in the container. The exact amount depends on the other processes running in the container.

--wiredTigerStatisticsLogDelaySecs <seconds>¶

Default: 0

New in version 3.0.0.

Specifies the interval, in seconds, at which WiredTiger logs statistics to the file specified in the dbPath or --dbpath. When --wiredTigerStatisticsLogDelaySecs is set to 0, WiredTiger does not log statistics.

--wiredTigerJournalCompressor <compressor>¶

Default: snappy

New in version 3.0.0.

Specifies the type of compression to use to compress WiredTiger journal data.

Available compressors are:

none
snappy
zlib

--wiredTigerDirectoryForIndexes¶

New in version 3.0.0.

When you start mongod with --wiredTigerDirectoryForIndexes, mongod stores indexes and collections in separate subdirectories under the data (i.e. --dbpath`) directory. Specifically, mongod stores the indexes in a subdirectory named index and the collection data in a subdirectory named collection.

By using a symbolic link, you can specify a different location for the indexes. Specifically, when mongod instance is not running, move the index subdirectory to the destination and create a symbolic link named index under the data directory to the new destination.

--wiredTigerCollectionBlockCompressor <compressor>¶

Default: snappy

New in version 3.0.0.

Specifies the default type of compression to use to compress collection data. You can override this on a per-collection basis when creating collections.

Available compressors are:

none
snappy
zlib

--wiredTigerCollectionBlockCompressor affects all collections created. If you change the value of --wiredTigerCollectionBlockCompressor on an existing MongoDB deployment, all new collections will use the specified compressor. Existing collections will continue to use the compressor specified when they were created, or the default compressor at that time.

--wiredTigerIndexPrefixCompression <boolean>¶

Default: true

New in version 3.0.0.

Enables or disables prefix compression for index data.

Specify true for --wiredTigerIndexPrefixCompression to enable prefix compression for index data, or false to disable prefix compression for index data.

The --wiredTigerIndexPrefixCompression setting affects all indexes created. If you change the value of --wiredTigerIndexPrefixCompression on an existing MongoDB deployment, all new indexes will use prefix compression. Existing indexes are not affected.

Replication Options¶

--replSet <setname>¶

Configures replication. Specify a replica set name as an argument to this set. All hosts in the replica set must have the same set name.

If your application connects to more than one replica set, each set should have a distinct name. Some drivers group replica set connections by replica set name.

--oplogSize <value>¶

Specifies a maximum size in megabytes for the replication operation log (i.e., the oplog). The mongod process creates an oplog based on the maximum amount of space available. For 64-bit systems, the oplog is typically 5% of available disk space. Once the mongod has created the oplog for the first time, changing the --oplogSize option will not affect the size of the oplog.

See Oplog Size for more information.

--replIndexPrefetch¶

Default: all

Storage Engine Specific Feature

--replIndexPrefetch is only available with the mmapv1 storage engine.

Determines which indexes secondary members of a replica set load into memory before applying operations from the oplog. By default secondaries load all indexes related to an operation into memory before applying operations from the oplog.

Set this option to one of the following:

Value	Description
`none`	Secondaries do not load indexes into memory.
`all`	Secondaries load all indexes related to an operation.
`_id_only`	Secondaries load no additional indexes into memory beyond the already existing `_id` index.

--enableMajorityReadConcern¶: New in version 3.2.

Enables read concern level of "majority". By default, "majority" level is not enabled.

Master-Slave Replication¶

These options provide access to conventional master-slave database replication. While this functionality remains accessible in MongoDB, replica sets are the preferred configuration for database replication.

--master¶: Configures the mongod to run as a replication master.

--slave¶: Configures the mongod to run as a replication slave.

--source <host><:port>¶: For use with the --slave option, the --source option designates the server that this instance will replicate.

--only <arg>¶: For use with the --slave option, the --only option specifies only a single database to replicate.

--slavedelay <value>¶: For use with the --slave option, the --slavedelay option configures a “delay” in seconds, for this slave to wait to apply operations from the master node.

--autoresync¶

For use with the --slave option. When set, the --autoresync option allows this slave to automatically resync if it is more than 10 seconds behind the master. This setting may be problematic if the --oplogSize specifies a too small oplog.

If the oplog is not large enough to store the difference in changes between the master’s current state and the state of the slave, this instance will forcibly resync itself unnecessarily. If you don’t specify --autoresync, the slave will not attempt an automatic resync more than once in a ten minute period.

--fastsync¶: In the context of replica set replication, set this option if you have seeded this member with an up-to-date copy of the entire dbPath of another member of the set. Otherwise the mongod will attempt to perform an initial sync, as though the member were a new member.

Warning

If the data is not perfectly synchronized and the mongod starts with fastsync, then the secondary or slave will be permanently out of sync with the primary, which may cause significant consistency problems.

Sharded Cluster Options¶

--configsvr¶

Declares that this mongod instance serves as the config database of a sharded cluster. When running with this option, clients (i.e. other cluster components) will not be able to write data to any database other than config and admin. The default port for a mongod with this option is 27019 and the default --dbpath directory is /data/configdb, unless specified.

If using MMAPv1 Storage Engine, --configsvr option also sets --smallfiles.

The --configsvr option creates a local oplog.

Do not use the --configsvr option with --shardsvr. Config servers cannot be a shard server.

Changed in version 3.2: Starting in MongoDB 3.2, config servers for sharded clusters can be deployed as a replica set. The replica set config servers must run the WiredTiger storage engine. MongoDB 3.2 deprecates the use of three mirrored mongod instances for config servers.

In previous versions, --configsvr could not be used in conjunction with --replSet.

--configsvrMode <string>¶

New in version 3.2.

If set to sccc, indicates that the config servers are deployed as three mirrored mongod instances, even if one or more config servers is also a member of a replica set. configsvrMode only accepts the value sccc.

If unset, config servers running as replica sets expect to use the “config server replica set” protocol for writing to config servers, rather than the “mirrored mongod” write protocol.

--shardsvr¶: Configures this mongod instance as a shard in a partitioned cluster. The default port for these instances is 27018. The only effect of --shardsvr is to change the port number.

--moveParanoia¶

If specified, during chunk migration, a shard saves, to the moveChunk directory of the --dbpath, all documents migrated from that shard.

MongoDB does not automatically delete the data saved in the moveChunk directory.

--noMoveParanoia¶: Changed in version 3.2: Starting in 3.2, MongoDB uses --noMoveParanoia as the default.

During chunk migration, a shard does not save documents migrated from the shard.

TLS/SSL Options¶

See

Configure mongod and mongos for TLS/SSL for full documentation of MongoDB’s support.

--sslOnNormalPorts¶

Deprecated since version 2.6.

Enables TLS/SSL for mongod.

With --sslOnNormalPorts, a mongod requires TLS/SSL encryption for all connections on the default MongoDB port, or the port specified by --port. By default, --sslOnNormalPorts is disabled.

Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.

--sslMode <mode>¶

New in version 2.6.

Enables TLS/SSL or mixed TLS/SSL used for all network connections. The argument to the --sslMode option can be one of the following:

Value	Description
`disabled`	The server does not use TLS/SSL.
`allowSSL`	Connections between servers do not use TLS/SSL. For incoming connections, the server accepts both TLS/SSL and non-TLS/non-SSL.
`preferSSL`	Connections between servers use TLS/SSL. For incoming connections, the server accepts both TLS/SSL and non-TLS/non-SSL.
`requireSSL`	The server uses and accepts only TLS/SSL encrypted connections.

Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.

--sslPEMKeyFile <filename>¶

Specifies the .pem file that contains both the TLS/SSL certificate and key. Specify the file name of the .pem file using relative or absolute paths.

You must specify --sslPEMKeyFile when TLS/SSL is enabled.

Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.

--sslPEMKeyPassword <value>¶: Specifies the password to de-crypt the certificate-key file (i.e. --sslPEMKeyFile). Use the --sslPEMKeyPassword option only if the certificate-key file is encrypted. In all cases, the mongod will redact the password from all logging and reporting output.

Changed in version 2.6: If the private key in the PEM file is encrypted and you do not specify the --sslPEMKeyPassword option, the mongod will prompt for a passphrase. See SSL Certificate Passphrase.

Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.

--clusterAuthMode <option>¶

Default: keyFile

New in version 2.6.

The authentication mode used for cluster authentication. If you use internal x.509 authentication, specify so here. This option can have one of the following values:

Value	Description
`keyFile`	Use a keyfile for authentication. Accept only keyfiles.
`sendKeyFile`	For rolling upgrade purposes. Send a keyfile for authentication but can accept both keyfiles and x.509 certificates.
`sendX509`	For rolling upgrade purposes. Send the x.509 certificate for authentication but can accept both keyfiles and x.509 certificates.
`x509`	Recommended. Send the x.509 certificate for authentication and accept only x.509 certificates.

Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.

--sslClusterFile <filename>¶

New in version 2.6.

Specifies the .pem file that contains the x.509 certificate-key file for membership authentication for the cluster or replica set.

If --sslClusterFile does not specify the .pem file for internal cluster authentication, the cluster uses the .pem file specified in the --sslPEMKeyFile option.

Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.

--sslClusterPassword <value>¶

New in version 2.6.

Specifies the password to de-crypt the x.509 certificate-key file specified with --sslClusterFile. Use the --sslClusterPassword option only if the certificate-key file is encrypted. In all cases, the mongod will redact the password from all logging and reporting output.

If the x.509 key file is encrypted and you do not specify the --sslClusterPassword option, the mongod will prompt for a passphrase. See SSL Certificate Passphrase.

Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.

--sslCAFile <filename>¶: New in version 2.4.

Specifies the .pem file that contains the root certificate chain from the Certificate Authority. Specify the file name of the .pem file using relative or absolute paths.

Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.

Warning

If the --sslCAFile option and its target file are not specified, x.509 client and member authentication will not function. mongod, and mongos in sharded systems, will not be able to verify the certificates of processes connecting to it against the trusted certificate authority (CA) that issued them, breaking the certificate chain.

As of version 2.6.4, mongod will not start with x.509 authentication enabled if the CA file is not specified.

--sslCRLFile <filename>¶: New in version 2.4.

Specifies the the .pem file that contains the Certificate Revocation List. Specify the file name of the .pem file using relative or absolute paths.

Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.

--sslAllowInvalidCertificates¶

New in version 2.6.

Bypasses the validation checks for TLS/SSL certificates on other servers in the cluster and allows the use of invalid certificates.

When using the --sslAllowInvalidCertificates setting, MongoDB logs a warning regarding the use of the invalid certificate.

Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.

--sslAllowInvalidHostnames¶: New in version 3.0.

Disables the validation of the hostnames in TLS/SSL certificates, when connecting to other mongod instances for inter-process authentication. This allows mongod to connect to other mongod instances if the hostnames in their certificates do not match their configured hostname.

Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.

--sslAllowConnectionsWithoutCertificates¶

New in version 2.4.

Changed in version 3.0.0: --sslWeakCertificateValidation became --sslAllowConnectionsWithoutCertificates. For compatibility, MongoDB processes continue to accept --sslWeakCertificateValidation, but all users should update their configuration files.

Disables the requirement for TLS/SSL certificate validation that --sslCAFile enables. With the --sslAllowConnectionsWithoutCertificates option, the mongod will accept connections when the client does not present a certificate when establishing the connection.

If the client presents a certificate and the mongod has --sslAllowConnectionsWithoutCertificates enabled, the mongod will validate the certificate using the root certificate chain specified by --sslCAFile and reject clients with invalid certificates.

Use the --sslAllowConnectionsWithoutCertificates option if you have a mixed deployment that includes clients that do not or cannot present certificates to the mongod.

Changed in version 3.0: Most MongoDB distributions now include support for TLS/SSL. See Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients for more information about TLS/SSL and MongoDB.

--sslDisabledProtocols <protocol(s)>¶

New in version 3.0.7.

Prevents a MongoDB server running with SSL from accepting incoming connections that use a specific protocol or protocols. --sslDisabledProtocols recognizes the following protocols: TLS1_0, TLS1_1, and TLS1_2. Specifying an unrecognized protocol will prevent the server from starting.

To specify multiple protocols, use a comma separated list of protocols.

Members of replica sets and sharded clusters must speak at least one protocol in common.

Audit Options¶

--auditDestination¶

New in version 2.6.

Enables auditing and specifies where mongod sends all audit events.

--auditDestination can have one of the following values:

Value Description

syslog

Output the audit events to syslog in JSON format. Not available on Windows. Audit messages have a syslog severity level of info and a facility level of user.

The syslog message limit can result in the truncation of audit messages. The auditing system will neither detect the truncation nor error upon its occurrence.

console Output the audit events to stdout in JSON format.

file Output the audit events to the file specified in --auditPath in the format specified in --auditFormat.

Note

Available only in MongoDB Enterprise.

--auditFormat¶

New in version 2.6.

Specifies the format of the output file for auditing if --auditDestination is file. The --auditFormat option can have one of the following values:

Value	Description
`JSON`	Output the audit events in JSON format to the file specified in --auditPath.
`BSON`	Output the audit events in BSON binary format to the file specified in --auditPath.

Printing audit events to a file in JSON format degrades server performance more than printing to a file in BSON format.

Note

Available only in MongoDB Enterprise.

--auditPath¶: New in version 2.6.

Specifies the output file for auditing if --auditDestination has value of file. The --auditPath option can take either a full path name or a relative path name.

Note

Available only in MongoDB Enterprise.

--auditFilter¶

New in version 2.6.

Specifies the filter to limit the types of operations the audit system records. The option takes a string representation of a query document of the form:

{ <field1>: <expression1>, ... }

The <field> can be any field in the audit message, including fields returned in the param document. The <expression> is a query condition expression.

To specify an audit filter, enclose the filter document in single quotes to pass the document as a string.

To specify the audit filter in a configuration file, you must use the YAML format of the configuration file.

Note

Available only in MongoDB Enterprise.

SNMP Options¶

--snmp-subagent¶: Runs SNMP as a subagent. For more information, see Monitor MongoDB With SNMP on Linux.

--snmp-master¶: Runs SNMP as a master. For more information, see Monitor MongoDB With SNMP on Linux.

inMemory Options¶

--inMemorySizeGB <integer>¶

Default: 60% of physical RAM less 1 GB

New in version 3.2.

Maximum amount of memory to allocate for In-Memory Storage Engine data and indexes.

--inMemoryStatisticsLogDelaySecs <integer>¶

Default: 0, do not log statistics.

New in version 3.2.

Seconds to wait between each write to a In-Memory Storage Engine statistics file in the --dbpath.

Encryption Key Management Options¶

--enableEncryption <boolean>¶

Default: False

New in version 3.2.

Enables encryption for the WiredTiger storage engine. You must set to true to pass in encryption keys and configurations.

Enterprise Feature

Available in MongoDB Enterprise only.

--encryptionCipherMode <string>¶

Default: AES256-CBC

New in version 3.2.

The cipher mode to use for encryption at rest:

Mode	Description
`AES256-CBC`	256-bit Advanced Encryption Standard in Cipher Block Chaining Mode
`AES256-GCM`	256-bit Advanced Encryption Standard in Galois/Counter Mode

Enterprise Feature

Available in MongoDB Enterprise only.

--encryptionKeyFile <string>¶

New in version 3.2.

The path to the local keyfile when managing keys via process other than KMIP. Only set when managing keys via process other than KMIP. If data is already encrypted using KMIP, MongoDB will throw an error.

Requires enableEncryption to be true.

Enterprise Feature

Available in MongoDB Enterprise only.

--kmipKeyIdentifier <string>¶

New in version 3.2.

Unique KMIP identifier for an existing key within the KMIP server. Include to use the key associated with the identifier as the system key. You can only use the setting the first time you enable encryption for the mongod instance. Requires enableEncryption to be true.

If unspecified, MongoDB will request that the KMIP server create a new key to utilize as the system key.

If the KMIP server cannot locate a key with the specified identifier or the data is already encrypted with a key, MongoDB will throw an error

Enterprise Feature

Available in MongoDB Enterprise only.

--kmipRotateMasterKey <boolean>¶

Default: False

New in version 3.2.

If true, rotate the master key and re-encrypt the internal keystore.

Enterprise Feature

Available in MongoDB Enterprise only.

Text Search Options¶

--basisTechRootDirectory <path>¶: New in version 3.2.

Specify the root directory of the Basis Technology Rosette Linguistics Platform installation to support additional languages for text search operations.

Enterprise Feature

Available in MongoDB Enterprise only.

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mongod¶

Synopsis¶

Options¶

Core Options¶

Storage Options¶

WiredTiger Options¶

Replication Options¶

Master-Slave Replication¶

Sharded Cluster Options¶

TLS/SSL Options¶

Audit Options¶

SNMP Options¶

inMemory Options¶

Encryption Key Management Options¶

Text Search Options¶

`mongod`¶