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Back Up and Restore with MongoDB Tools¶
This document describes the process for creating backups and restoring data using the utilities provided with MongoDB.
Because all of these tools primarily operate by interacting with a running
mongod instance, they can impact the performance of your
running database.
Not only do they create traffic for a running database instance, they also force the database to read all data through memory. When MongoDB reads infrequently used data, it can supplant more frequently accessed data, causing a deterioration in performance for the database’s regular workload.
No matter how you decide to import or export your data, consider the following guidelines:
- Label files so that you can identify the contents of the export or backup as well as the point in time the export/backup reflect.
- Do not create or apply exports if the backup process itself will have an adverse effect on a production system.
- Make sure that the backups reflect a consistent data state. Export or backup processes can impact data integrity (i.e. type fidelity) and consistency if updates continue during the backup process.
- Test backups and exports by restoring and importing to ensure that the backups are useful.
See also
MongoDB Backup Methods or MongoDB Cloud Manager Backup documentation for more information on backing up MongoDB instances. Additionally, consider the following references for the MongoDB import/export tools:
Binary BSON Dumps¶
The mongorestore and mongodump utilities work with
BSON data dumps, and are useful for creating
backups of small deployments. For resilient and non-disruptive backups, use a
file system or block-level disk snapshot function, such as the methods
described in the MongoDB Backup Methods document.
Use these tools for backups if other backup methods, such as the MongoDB Cloud Manager or file system snapshots are unavailable.
Backup a Database with mongodump¶
Required Access¶
To run mongodump against a MongoDB deployment that has
access control enabled, you must have
privileges that grant find action for each database to
back up. The built-in backup role provides the required
privileges to perform backup of any and all databases.
Changed in version 3.0.9: The backup role provides additional privileges to back
up the system.profile
collections that exist when running with database profiling. Previously, users required an additional
read access on this collection.
Basic mongodump Operations¶
The mongodump utility backs up data by connecting to a
running mongod or mongos instance.
The utility can create a backup for an entire server, database or collection, or can use a query to backup just part of a collection.
When you run mongodump without any arguments, the command
connects to the MongoDB instance on the local system
(e.g. 127.0.0.1 or localhost) on port 27017 and creates a
database backup named dump/ in the current directory.
To backup data from a mongod or mongos instance
running on the same machine and on the default port of 27017,
use the following command:
The data format used by mongodump from version 2.2 or
later is incompatible with earlier versions of mongod.
Do not use recent versions of mongodump to back up older
data stores.
You can also specify the --host and
--port of the MongoDB instance that the
mongodump should connect to. For example:
mongodump will write BSON files that hold a copy of
data accessible via the mongod listening on port 27017 of
the mongodb.example.net host. See Create Backups from Non-Local mongod Instances for more
information.
To specify a different output directory, you can use the --out
or -o option:
To limit the amount of data included in the database dump, you can
specify --db and
--collection as options to
mongodump. For example:
This operation creates a dump of the collection named myCollection
from the database test in a dump/ subdirectory of the
current working directory.
mongodump overwrites output files if they exist in the
backup data folder. Before running the mongodump command
multiple times, either ensure that you no longer need the files in the
output folder (the default is the dump/ folder) or rename the
folders or files.
Point in Time Operation Using Oplogs¶
Use the --oplog option with
mongodump to collect the oplog entries to build a
point-in-time snapshot of a database within a replica set. With --oplog, mongodump copies all the data from
the source database as well as all of the oplog entries from
the beginning to the end of the backup procedure. This operation, in
conjunction with mongorestore --oplogReplay,
allows you to restore a backup that reflects the specific
moment in time that corresponds to when mongodump completed
creating the dump file.
Create Backups from Non-Local mongod Instances¶
The --host and
--port options for
mongodump allow you to connect to and backup from a remote host.
Consider the following example:
On any mongodump command you may, as above, specify username
and password credentials to specify database authentication.
Restore a Database with mongorestore¶
Access Control¶
To restore data to a MongoDB deployment that has access control enabled, the restore role provides
access to restore any database if the backup data does not include
system.profile collection data.
If the backup data includes system.profile collection data and the target database
does not contain the system.profile
collection, mongorestore attempts to create the collection
even though the program does not actually restore system.profile
documents. As such, the user requires additional privileges to perform
createCollection and convertToCapped
actions on the system.profile
collection for a database.
If running mongorestore with --oplogReplay,
create a user-defined role that
has anyAction on anyResource and grant
only to users who must run mongorestore with
--oplogReplay.
Basic mongorestore Operations¶
The mongorestore utility restores a binary backup created by
mongodump. By default, mongorestore looks for a
database backup in the dump/ directory.
The mongorestore utility restores data by connecting to a
running mongod or mongos directly.
mongorestore can restore either an entire database backup
or a subset of the backup.
To use mongorestore to connect to an active
mongod or mongos, use a command with the following prototype form:
Consider the following example:
Here, mongorestore imports the database backup in
the dump-2013-10-25 directory to the mongod instance
running on the localhost interface.
Restore Point in Time Oplog Backup¶
If you created your database dump using the --oplog option to ensure a point-in-time snapshot, call
mongorestore with the
--oplogReplay
option, as in the following example:
You may also consider using the mongorestore --objcheck
option to check the integrity of objects while inserting them into the
database, or you may consider the mongorestore --drop option to drop each
collection from the database before restoring from
backups.
Restore Backups to Non-Local mongod Instances¶
By default, mongorestore connects to a MongoDB instance
running on the localhost interface (e.g. 127.0.0.1) and on the
default port (27017). If you want to restore to a different host or
port, use the --host and --port options.
Consider the following example:
As above, you may specify username and password connections if your
mongod requires authentication.
Human Intelligible Import/Export Formats¶
MongoDB’s mongoimport and mongoexport tools allow you to
work with your data in a human-readable
Extended JSON or CSV format.
This is useful for simple ingestion to or from a third-party system, and when
you want to backup or export a small subset of your data. For more complex data
migration tasks, you may want to write your own import and export scripts using
a client driver to interact with the database.
The examples in this section use the MongoDB tools
mongoimport and
mongoexport. These tools may also be useful
for importing data into a MongoDB database from third party
applications.
If you want to simply copy a database or collection from one instance
to another, consider using the copydb, clone,
or cloneCollection commands, which may be more suited to
this task. The mongo shell provides the
db.copyDatabase() method.
Warning
Avoid using mongoimport and mongoexport for
full instance production backups. They do not reliably preserve all rich
BSON data types, because JSON can only represent a subset
of the types supported by BSON. Use mongodump
and mongorestore as described in MongoDB Backup Methods for this
kind of functionality.
Collection Export with mongoexport¶
Export in CSV Format¶
Changed in version 3.0.0: mongoexport removed the --csv option. Use the
--type=csv option to specify CSV format
for the output.
In the following example, mongoexport exports data from the
collection contacts collection in the users database in CSV
format to the file /opt/backups/contacts.csv.
The mongod instance that mongoexport connects to is
running on the localhost port number 27017.
When you export in CSV format, you must specify the fields in the documents
to export. The operation specifies the name and address fields
to export.
For CSV exports only, you can also specify the fields in a file containing the line-separated list of fields to export. The file must have only one field per line.
For example, you can specify the name and address fields in a
file fields.txt:
Then, using the --fieldFile option, specify the fields to export with
the file:
Changed in version 3.0.0: mongoexport removed the --csv option and replaced with
the --type option.
Export in JSON Format¶
This example creates an export of the contacts collection from the
MongoDB instance running on the localhost port number 27017. This
writes the export to the contacts.json file in JSON format.
Export from Remote Host Running with Authentication¶
The following example exports the contacts collection from the
marketing database, which requires authentication.
This data resides on the MongoDB instance located on the host
mongodb1.example.net running on port 37017, which requires the username
user and the password pass.
Export Query Results¶
You can export only the results of a query by supplying a query filter with
the --query option, and limit the results to a single
database using the “--db” option.
For instance, this command returns all documents in the sales database’s
contacts collection that contain a field named field with a value
of 1.
You must enclose the query in single quotes (e.g. ') to ensure that it does
not interact with your shell environment.
Collection Import with mongoimport¶
Simple Usage¶
mongoimport restores a database from a backup taken with
mongoexport. Most of the arguments to mongoexport also
exist for mongoimport.
In the following example, mongoimport imports the data in
the JSON data from the contacts.json file into the collection
contacts in the users database.
Import JSON to Remote Host Running with Authentication¶
In the following example, mongoimport imports data from the
file /opt/backups/mdb1-examplenet.json into the contacts collection
within the database marketing on a remote MongoDB
database with authentication enabled.
mongoimport connects to the mongod instance running on
the host mongodb1.example.net over port 37017. It authenticates with the
username user and the password pass.
CSV Import¶
In the following example, mongoimport imports the csv
formatted data in the /opt/backups/contacts.csv file into the
collection contacts in the users database on the MongoDB
instance running on the localhost port numbered
27017.
Specifying --headerline instructs
mongoimport to determine the name of the fields using the first
line in the CSV file.
mongoimport uses the input file name, without the
extension, as the collection name if -c or --collection is
unspecified. The following example is therefore equivalent:
Use the “--ignoreBlanks” option
to ignore blank fields. For CSV and TSV imports, this
option provides the desired functionality in most cases because it avoids
inserting fields with null values into your collection.