Today I would like to tell my readers about a database management system that requires no table schema description. That’s right – I’m talking about MongoDB. A DBMS is considered one of the classic examples of NoSQL systems. Its documents are made up of key-value pairs, which are the basic unit of data in MongoDB. Its collections contain groups of documents and functions that are equivalent to tables in relational databases. MongoDB is a database that emerged in the mid-2000s. The installation instructions can be found in the official guide below.
In this article, I would like to show you how to back up data and then restore it. The guide was developed on a computer with the Ubuntu 20.04.2 LTS operating system.
BSON makes working with data faster: it provides faster searching and processing. Although, it should be noted that BSON, in contrast to JSON, has a slight drawback: in general, JSON data takes up less space than that in BSON; on the other hand, the high speed of BSON fully compensates for this disadvantage.
So, let’s connect to our MongoDB and create three databases for backups. They will be DB1, DB2, and DB3. To fill these databases, let’s add some collections.
use DB1 db.createCollection("posts1") db.createCollection("address1") db.createCollection("phone1") use DB2 db.createCollection("posts2") db.createCollection("address2") db.createCollection("phone2") use DB3 db.createCollection("posts3") db.createCollection("address3") db.createCollection("phone3")
We’ve created our databases. Now let’s check if everything is fine:
use admin show dbs
As you can see, our databases are okay. Now let’s check if they have the collections that we have created before.
use DB1 show collections use DB2 show collections use DB3 show collections
All the collections are there. Now we can proceed to the first backup option.
To make a backup copy, log in as root. Now create a directory for storing backup:
Now use the following command to create a backup:
mongodump --host=localhost --gzip --db DB1 --archive=/tmp/backup_v1/backup-db-1.gz
Now, after creating a backup, let’s move to the database directory and see what it has using the following command:
ls -la /tmp/backup_v1
As you can see, our Backup Copy has just been created.
Now, to restore data from this kind of backup we use the following command:
mongorestore --gzip --archive=/tmp/backup_v1/backup-db-1.gz
In this example, we use only one command to make a backup copy, which is then archived. There are several options for how to make a backup copy.
In this article, we will discuss them one by one.
Let’s create a directory for storing backup:
Use the following command to back up:
mongodump --out /tmp/backup_v2
After successful backup, let’s move to the database directory and see what it has. It has BSON and JSON collections without compression.
ls -la /tmp/backup_v2/DB1
Now restore data from this backup using the following command:
mongorestore --drop --dir /tmp/backup_v2
Here, the --drop parameter is used to drop a collection before importing (if it exists) to avoid duplicate key errors. This --drop parameter should be used with caution.
Now restore a specific collection (for example, posts1 from DB1) from a backup of all databases:
mongorestore --drop --dir /tmp/backup_v2 --nsInclude 'DB1.posts1'
Restore all databases and all collections except for a specific collection (for example, posts1 from DB1):
mongorestore --drop --dir /tmp/backup_v2 --nsExclude 'DB1.posts1'
Now create a backup and compress the backup file:
mkdir /tmp/backup_v3 mongodump --gzip --out /tmp/backup_v3
Now view the backup file:
ls -la /tmp/backup_v3/DB1
Here the backup file contains compressed files.
Now, to restore data from this kind of backup:
mongorestore --gzip --drop --dir /tmp/backup_v3
Create a backup of all the databases with compression into a single archive (.gz):
mkdir /tmp/backup_v4/ mongodump --gzip --archive=/tmp/backup_v4/my_backup.gz
Now, restore data from the backup using the following command:
mongorestore --gzip --drop --archive=/tmp/backup_v4/my_backup.gz
Create a backup of a specific database
mkdir /tmp/backup_v5 mongodump --gzip --out /tmp/backup_v5 --db DB2
Restore data from this backup:
mongorestore --gzip --drop --dir /tmp/backup_v5
Create a backup a single address2 collection from DB2
mkdir /tmp/backup_v6 mongodump --gzip --out /tmp/backup_v6 --db DB2 -c address2
Create a back up the entire DB2 except for a single posts2 collection
mkdir /tmp/backup_v7 mongodump --gzip --out /tmp/backup_v7 --db DB2 --excludeCollection posts2
I hope this article will help you understand how to work with this DBMS, and you can successfully deal with the task if necessary. Thank you all for reading this article!