使用 mongodump 和 mongorestore备份和恢复 MongoDB 数据库

Basic mongodump Operations¶

The mongodump utility can perform a live backup of data or can work against an inactive set of database files. The mongodump utility can create a dump for an entire server/database/collection (or part of a collection using of query), even when the database is running and active. If you run mongodump without any arguments, the command connects to the local database instance (e.g. 127.0.0.1 or localhost) and creates a database backup named dump/ in the current directory.

To limit the amount of data included in the database dump, you can specify --db and --collection as options to the mongodump command. For example:

mongodump --collection collection --db test

This command creates a dump of the collection named collection from the database test in a dump/ subdirectory of the current working directory.

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 of the backup procedure to until the backup procedure completes. This backup procedure, in conjunction with mongorestore --oplogReplay, allows you to restore a backup that reflects a consistent and specific moment in time.

Create Backups Without a Running mongod Instance¶

If your MongoDB instance is not running, you can use the --dbpath option to specify the location to your MongoDB instance’s database files. mongodump reads from the data files directly with this operation. This locks the data directory to prevent conflicting writes. The mongod process must not be running or attached to these data files when you run mongodump in this configuration. Consider the following example:

mongodump --dbpath /srv/mongodb

Create Backups from Non-Local mongod Instances¶

The --host and --port options for mongodump allow you to specify a non-local host to connect to capture the dump. Consider the following example:

mongodump --host mongodb1.example.net --port 3017 --username user --password pass --out /opt/backup/mongodump-2011-10-24

On any mongodump command you may, as above, specify username and password credentials to specify database authentication.

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:

mongorestore --oplogReplay

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 a Subset of data from a Binary Database Dump¶

mongorestore also includes the ability to a filter to all input before inserting it into the new database. Consider the following example:

mongorestore --filter '{"field": 1}'

Here, mongorestore only adds documents to the database from the dump located in the dump/ folder if the documents have a field name field that holds a value of 1. Enclose the filter in single quotes (e.g. ') to prevent the filter from interacting with your shell environment.

Restore without a Running mongod¶

mongorestore can write data to MongoDB data files without needing to connect to a mongod directly.

mongorestore --dbpath /srv/mongodb --journal

Here, mongorestore restores the database dump located in dump/ folder into the data files located at /srv/mongodb. Additionally, the --journal option ensures that mongorestore records all operation in the durability journal. The journal prevents data file corruption if anything (e.g. power failure, disk failure, etc.) interrupts the restore operation.