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mongostat
mongostat
¶
On this page
macOS Sierra and Go 1.6 Incompatibility
Users running on macOS Sierra require the 3.2.10 or newer version of mongostat.
Synopsis¶
The mongostat
utility provides a quick overview of the
status of a currently running mongod
or mongos
instance. mongostat
is functionally similar to the
UNIX/Linux file system utility vmstat
, but provides data regarding
mongod
and mongos
instances.
Run mongostat
from the system command line, not the mongo
shell.
Required Access¶
In order to connect to a mongod
that enforces authorization
with the --auth
option, specify the
--username
and --password
options, and the connecting user must have the
serverStatus
privilege action on the cluster resources.
The built-in role clusterMonitor
provides this privilege as
well as other privileges. To create a role with just the privilege to
run mongostat
, see Create a Role to Run mongostat.
Options¶
-
mongostat
¶
-
--help
¶
Returns information on the options and use of mongostat.
-
--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
.)
-
--version
¶
Returns the mongostat release number.
-
--uri
<connectionString>
¶ New in version 3.4.6.
Specify a resolvable URI connection string to connect to the MongoDB deployment.
For more information on the components of the connection string, see the Connection String URI Format documentation.
Important
The following command-line options cannot be used in conjunction with
--uri
option:--host
--port
--username
--password
(if the URI connection string also includes the password)--authenticationDatabase
--authenticationMechanism
Instead, specify these options as part of your
--uri
connection string.
-
--host
<hostname><:port>
,
-h
<hostname><:port>
¶ Default: localhost:27017
Specifies a resolvable hostname for the
mongod
to which to connect. By default, the mongostat attempts to connect to a MongoDB instance running on the localhost on port number27017
.To connect to a replica set, you can specify the set member or members to report on, as in the following (see also the
--discover
flag):Changed in version 3.0.0: If you use IPv6 and use the
<address>:<port>
format, you must enclose the portion of an address and port combination in brackets (e.g.[<address>]
).
-
--port
<port>
¶ Default: 27017
Specifies the TCP port on which the MongoDB instance listens for client connections.
-
--ipv6
¶
Removed in version 3.0.
Enables IPv6 support and allows mongostat to connect to the MongoDB instance using an IPv6 network. Prior to MongoDB 3.0, you had to specify
--ipv6
to use IPv6. In MongoDB 3.0 and later, IPv6 is always enabled.
-
--ssl
¶
New in version 2.6.
Enables connection to a
mongod
ormongos
that has TLS/SSL support enabled.For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .
-
--sslCAFile
<filename>
¶ New in version 2.6.
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.Starting in version 3.4, if
--sslCAFile
orssl.CAFile
is not specified and you are not using x.509 authentication, the system-wide CA certificate store will be used when connecting to an TLS/SSL-enabled server.If using x.509 authentication,
--sslCAFile
orssl.CAFile
must be specified.Warning
Version 3.2 and earlier: For TLS/SSL connections (
--ssl
) tomongod
andmongos
, if the mongostat runs without the--sslCAFile
, mongostat will not attempt to validate the server certificates. This creates a vulnerability to expiredmongod
andmongos
certificates as well as to foreign processes posing as validmongod
ormongos
instances. Ensure that you always specify the CA file to validate the server certificates in cases where intrusion is a possibility.For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .
-
--sslPEMKeyFile
<filename>
¶ New in version 2.6.
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.This option is required when using the
--ssl
option to connect to amongod
ormongos
that hasCAFile
enabled withoutallowConnectionsWithoutCertificates
.For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .
-
--sslPEMKeyPassword
<value>
¶ New in version 2.6.
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 mongostat will redact the password from all logging and reporting output.If the private key in the PEM file is encrypted and you do not specify the
--sslPEMKeyPassword
option, the mongostat will prompt for a passphrase. See TLS/SSL Certificate Passphrase.For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .
-
--sslCRLFile
<filename>
¶ New in version 2.6.
Specifies the
.pem
file that contains the Certificate Revocation List. Specify the file name of the.pem
file using relative or absolute paths.For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .
-
--sslAllowInvalidCertificates
¶
New in version 2.6.
Bypasses the validation checks for server certificates and allows the use of invalid certificates. When using the
allowInvalidCertificates
setting, MongoDB logs as a warning the use of the invalid certificate.Starting in MongoDB 3.6.6, if you specify
--sslAllowInvalidCertificates
orssl.allowInvalidCertificates: true
when using x.509 authentication, an invalid certificate is only sufficient to establish a TLS/SSL connection but is insufficient for authentication.Warning
For TLS/SSL connections to
mongod
andmongos
, avoid using--sslAllowInvalidCertificates
if possible and only use--sslAllowInvalidCertificates
on systems where intrusion is not possible.If the
mongo
shell (and other MongoDB Tools) runs with the--sslAllowInvalidCertificates
option, themongo
shell (and other MongoDB Tools) will not attempt to validate the server certificates. This creates a vulnerability to expiredmongod
andmongos
certificates as well as to foreign processes posing as validmongod
ormongos
instances.For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .
-
--sslAllowInvalidHostnames
¶
New in version 3.0.
Disables the validation of the hostnames in TLS/SSL certificates. Allows mongostat to connect to MongoDB instances even if the hostname in their certificates do not match the specified hostname.
For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .
-
--sslFIPSMode
¶
New in version 2.6.
Directs the mongostat to use the FIPS mode of the installed OpenSSL library. Your system must have a FIPS compliant OpenSSL library to use the
--sslFIPSMode
option.Note
FIPS-compatible TLS/SSL is available only in MongoDB Enterprise. See Configure MongoDB for FIPS for more information.
-
--username
<username>
,
-u
<username>
¶ Specifies a username with which to authenticate to a MongoDB database that uses authentication. Use in conjunction with the
--password
and--authenticationDatabase
options.Note
You cannot specify both
--username
and--uri
.
-
--password
<password>
,
-p
<password>
¶ Specifies a password with which to authenticate to a MongoDB database that uses authentication. Use in conjunction with the
--username
and--authenticationDatabase
options.Changed in version 3.0.2: To prompt the user for the password, pass the
--username
option without--password
or specify an empty string as the--password
value, as in--password ""
.Note
You cannot specify both
--password
and--uri
.
-
--authenticationDatabase
<dbname>
¶ Specifies the authentication database where the specified
--username
has been created. See Authentication Database.Note
You cannot specify both
--authenticationDatabase
and--uri
.--authenticationDatabase
is required formongod
andmongos
instances that use Authentication.
-
--authenticationMechanism
<name>
¶ Default: SCRAM-SHA-1
Changed in version 2.6: Added support for the
PLAIN
andMONGODB-X509
authentication mechanisms.Changed in version 3.0: Added support for the
SCRAM-SHA-1
authentication mechanism. Changed default mechanism toSCRAM-SHA-1
.Specifies the authentication mechanism the mongostat instance uses to authenticate to the
mongod
ormongos
.Value Description SCRAM-SHA-1 RFC 5802 standard Salted Challenge Response Authentication Mechanism using the SHA1 hash function. MONGODB-CR MongoDB challenge/response authentication. (Deprecated in MongoDB 3.6) MONGODB-X509 MongoDB TLS/SSL certificate authentication. GSSAPI (Kerberos) External authentication using Kerberos. This mechanism is available only in MongoDB Enterprise. PLAIN (LDAP SASL) External authentication using LDAP. You can also use PLAIN
for authenticating in-database users.PLAIN
transmits passwords in plain text. This mechanism is available only in MongoDB Enterprise.Note
You cannot specify both
--authenticationMechanism
and--uri
.
-
--gssapiServiceName
¶
New in version 2.6.
Specify the name of the service using GSSAPI/Kerberos. Only required if the service does not use the default name of
mongodb
.This option is available only in MongoDB Enterprise.
-
--gssapiHostName
¶
New in version 2.6.
Specify the hostname of a service using GSSAPI/Kerberos. Only required if the hostname of a machine does not match the hostname resolved by DNS.
This option is available only in MongoDB Enterprise.
-
--humanReadable
boolean
¶ Default: true
New in version 3.4.
When
true
, mongostat formats dates and quantity values for easier reading, as in the following sample output:When
false
, mongostat returns the raw data, as in the following sample output:
-
-o
<field list>
¶ New in version 3.4.
When specified, mongostat includes only the specified fields in the mongostat output.
Use dot notation to specify
serverStatus fields
, as inmetrics.document.inserted
.To specify a custom name for a field, use
<field>=<customName>
, as in:-o
supports the following methods to modify the information returned for a given serverStatus field:-
rate
()¶ Use
.rate()
to view the rate per second at which a serverStatus field is changing frommongostat
call to call.View Rate of Change for a Field with .rate() illustrates how to use
mongostat
with-o
and the.rate()
method.
-
diff
()¶ Use
.diff()
to view how much a serverStatus field has changed since the previousmongostat
call. The interval between calls is specified by<sleeptime>
.View Field Changes with .diff() illustrates how to use
mongostat
with-o
and the.diff()
method.
mongostat supports specifying either
-o
or-O
: you cannot include both options.See Specify mongostat Output Fields for an example of
-o
.-
-
-O
<field list>
¶ New in version 3.4.
When specified, mongostat includes the specified
serverStatus
fields after the default mongostat output.Use dot notation to specify
serverStatus fields
, as inmetrics.document.inserted
.To specify a custom name for a field, use
<field>=<customName>
, as in:mongostat supports specifying either
-O
or-o
: you cannot include both options.See Add Fields to mongostat Output for an example of
-O
.
-
--noheaders
¶
Disables the output of column or field names.
-
--rowcount
<number>
,
-n
<number>
¶ Controls the number of rows to output. Use in conjunction with the
sleeptime
argument to control the duration of amongostat
operation.Unless
--rowcount
is specified,mongostat
will return an infinite number of rows (e.g. value of0
.)
-
--discover
¶
Discovers and reports on statistics from all members of a replica set or sharded cluster. When connected to any member of a replica set,
--discover
all non-hidden members of the replica set. When connected to amongos
,mongostat
will return data from all shards in the cluster. If a replica set provides a shard in the sharded cluster,mongostat
will report on non-hidden members of that replica set.The
mongostat --host
option is not required but potentially useful in this case.Changed in version 2.6: When running with
--discover
,mongostat
now respects--rowcount
.
-
--http
¶
Configures
mongostat
to collect data using the HTTP interface rather than a raw database connection.Changed in version 3.6: MongoDB 3.6 removes the deprecated HTTP interface and REST API to MongoDB.
-
--interactive
¶
New in version 3.4.
Display mongostat output in an interactive non-scrolling interface rather than the default scrolling output.
--interactive
is not available with the--json
option.See: View Statistics in an Interactive Interface for an example of
--interactive
.
-
<sleeptime>
¶
Default: 1
The final mongostat argument is the length of time, in seconds, that
mongostat
waits in between calls. By defaultmongostat
returns one call every second.mongostat
returns values that reflect the operations over a 1 second period. For values of<sleeptime>
greater than 1,mongostat
averages data to reflect average operations per second.
Fields¶
mongostat
returns values that reflect the operations over a
1 second period. When mongostat <sleeptime> has a value
greater than 1, mongostat
averages the statistics to reflect
average operations per second.
mongostat
outputs the following fields:
-
inserts
The number of objects inserted into the database per second. If followed by an asterisk (e.g.
*
), the datum refers to a replicated operation.
-
query
The number of query operations per second.
-
update
The number of update operations per second.
-
delete
The number of delete operations per second.
-
getmore
The number of get more (i.e. cursor batch) operations per second.
-
command
The number of commands per second. On slave and secondary systems,
mongostat
presents two values separated by a pipe character (e.g.|
), in the form oflocal|replicated
commands.
-
flushes
Changed in version 3.0.
For the WiredTiger Storage Engine,
flushes
refers to the number of WiredTiger checkpoints triggered between each polling interval.For the MMAPv1 Storage Engine,
flushes
represents the number of fsync operations per second.
-
dirty
New in version 3.0.
Only for WiredTiger Storage Engine. The percentage of the WiredTiger cache with dirty bytes, calculated by
wiredTiger.cache.tracked dirty bytes in the cache
/wiredTiger.cache.maximum bytes configured
.
-
used
New in version 3.0.
Only for WiredTiger Storage Engine. The percentage of the WiredTiger cache that is in use, calculated by
wiredTiger.cache.bytes currently in the cache
/wiredTiger.cache.maximum bytes configured
.
-
mapped
Changed in version 3.0.
Only for MMAPv1 Storage Engine. The total amount of data mapped in megabytes. This is the total data size at the time of the last
mongostat
call.
-
vsize
The amount of virtual memory in megabytes used by the process at the time of the last
mongostat
call.
-
non-mapped
Changed in version 3.0.
Only for MMAPv1 Storage Engine.
Optional. The total amount of virtual memory excluding all mapped memory at the time of the last
mongostat
call.mongostat
only returns this value when started with the--all
option.
-
res
The amount of resident memory in megabytes used by the process at the time of the last
mongostat
call.
-
faults
Changed in version 3.0.
Only for MMAPv1 Storage Engine. The number of page faults per second.
Changed in version 2.1: Before version 2.1, this value was only provided for MongoDB instances running on Linux hosts.
-
lr
New in version 3.2.
Only for MMAPv1 Storage Engine. The percentage of read lock acquisitions that had to wait.
mongostat
displayslr|lw
if a lock acquisition waited.
-
lw
New in version 3.2.
Only for MMAPv1 Storage Engine. The percentage of write lock acquisitions that had to wait.
mongostat
displayslr|lw
if a lock acquisition waited.
-
lrt
New in version 3.2.
Only for MMAPv1 Storage Engine. The average acquire time, in microseconds, of read lock acquisitions that waited.
mongostat
displayslrt|lwt
if a lock acquisition waited.
-
lwt
New in version 3.2.
Only for MMAPv1 Storage Engine. The average acquire time, in microseconds, of write lock acquisitions that waited.
mongostat
displayslrt|lwt
if a lock acquisition waited.
-
locked
Changed in version 3.0: Only appears when
mongostat
runs against pre-3.0 versions of MongoDB instances.The percent of time in a global write lock.
-
idx miss
Changed in version 3.0.
Only for MMAPv1 Storage Engine. The percent of index access attempts that required a page fault to load a btree node. This is a sampled value.
-
qr
The length of the queue of clients waiting to read data from the MongoDB instance.
-
qw
The length of the queue of clients waiting to write data from the MongoDB instance.
-
ar
The number of active clients performing read operations.
-
aw
The number of active clients performing write operations.
-
netIn
The amount of network traffic, in bytes, received by the MongoDB instance.
This includes traffic from
mongostat
itself.
-
netOut
The amount of network traffic, in bytes, sent by the MongoDB instance.
This includes traffic from
mongostat
itself.
-
conn
The total number of open connections.
-
set
The name, if applicable, of the replica set.
Examples¶
Specify mongostat
Collection Period and Frequency¶
In the first example, mongostat
will return data every
second for 20 seconds. mongostat
collects data from the
mongod
instance running on the localhost interface on
port 27017. All of the following invocations produce identical
behavior:
In the next example, mongostat
returns data every 5 minutes
(or 300 seconds) for as long as the program runs. mongostat
collects data from the mongod
instance running on the
localhost interface on port 27017
. The following
invocations produce identical behavior:
In the following example, mongostat
returns data every 5
minutes for an hour (12 times.) mongostat
collects data
from the mongod
instance running on the localhost interface
on port 27017. The following invocations produce identical
behavior:
Add Fields to mongostat
Output¶
New in version 3.4.
-O
allows you to specify fields from
serverStatus
output to add to the default
mongostat
output. The following example adds the host
and version
fields as well as the network.numRequests
field,
which will display as “network requests”, to the default
mongostat
output:
The mongostat
output would then resemble:
Specify mongostat
Output Fields¶
New in version 3.4.
-o
specifies the columns mongostat
includes in its
output. You can specify any serverStatus
field as a
mongostat
output column. The following example specifies the
host
, time
, and metrics.document.inserted
fields:
The mongostat
output would then resemble:
View Rate of Change for a Field with .rate()
¶
New in version 3.4.
.rate()
enables you to view the rate per second at which a
numerical field has changed from one mongostat
call to the
next. For example, you can view the rate at which documents have been
inserted during an insert operation. .rate()
can therefore
help you view the performance of your mongod
instance.
The following example reports on the rate of change of the
metrics.document.inserted
serverStatus
field. The
invocation uses -o
’s ability to specify the name of an column
to label metrics.document.inserted.rate()
as “inserted rate” and
metrics.document.inserted
as “inserted”:
The output would then resemble:
View Field Changes with .diff()
¶
New in version 3.4.
.diff()
returns the difference between the current
serverStatus
field value and the value from the previous
mongostat
call. The following example returns statistics on
the number of documents being inserted into a collection: inserted
diff
is the difference in the
metrics.document.inserted
field between subsequent
calls, while inserted
is the value of
metrics.document.inserted
:
The output would then resemble:
View Statistics for a Replica Set or Sharded Cluster¶
In many cases, using the --discover
option
will help provide a more complete snapshot of the state of an entire
group of machines. If a mongos
process connected to a
sharded cluster is running on port 27017
of the local
machine, you can use the following form to return statistics from all
members of the cluster:
View Statistics in an Interactive Interface¶
New in version 3.4.
Use the --interactive
option to
view statistics in a non-scrolling ncurses -style
interactive output. The --interactive
option lets you highlight specific
hosts, columns, or fields to view. When combined with --discover
,
--interactive
displays statistics for all members of a
replica set or sharded cluster, as in the following example:
The output for a sharded cluster would then resemble:
Additional Information¶
For more information about monitoring MongoDB, see Monitoring for MongoDB.
For more background on other MongoDB status outputs see:
For an additional utility that provides MongoDB metrics see mongotop.