# Backing Up an Instance

This page explains how to back up a MongoDB instance using DMK utilities.

***

#### Backup overview

DMK performs backups using the `dmk_dbbackup.py` script, which supports multiple modes, including full backups and dumps, with or without compression. Backups are stored in a designated backup directory, typically defined by the `MONGO_BACKUP_ROOT` environment variable.

***

#### Performing a backup

To perform a backup of a MongoDB instance, run the following:

```bash
mongodb@vm00:/home/mongodb/ [mdb01] dmk_dbbackup.py -i mdb01
2025-06-30 04:18:41 | INFO     | Backup MongoDB instance mdb01 with options: 'None'.
2025-06-30 04:18:41 | INFO     | Backup command: /u01/app/mongodb/product/8.0.16/bin/mongodump --uri="mongodb://<username>:<password>@127.0.0.1:27017/?tls=true&tlsCertificateKeyFile=/u01/app/mongodb/admin/mdb01/secret/mongo-x509/clients/clientUser.pem&tlsCAFile=/u01/app/mongodb/admin/mdb01/secret/mongo-x509/ca/ca.pem" --out /u90/mongodb/backup/mdb01/backup_mdb01_20250630_041841
2025-06-30 04:18:41 | INFO     | Backup directory: '/u90/mongodb/backup/mdb01/backup_mdb01_20250630_041841'
2025-06-30 04:18:41 | INFO     | Backup MongoDB instance mdb01 in progress...
2025-06-30 04:18:41 | INFO     | Backup completed successfully.
```

By default, the script performs a full, uncompressed `mongodump` of the MongoDB instance.

***

#### Common options

* `-d, --instance_name <name>`: **(Required)** Name of the MongoDB instance. It must match the value of the `MONGO_INSTANCE` environment variable.
* `-a, --archive`: If present, generates the dump with the `mongodump --archive` option instead of `mongodump --out`. A single archive file will be generated instead of multiple BSON files.
* `-o, --mongodump_options "<options>"`: Extra options to pass to the `mongodump` command (e.g. `--gzip`, `--archive`, etc.).

Example:

```bash
$DMK_HOME/bin/dmk_dbbackup.py -i mdb01 -o="--gzip"
```

***

#### Backup location

Backups are stored in `$MONGO_BACKUP_ROOT/<instance_name>/backup_<instance_name>_YYYYMMDD_hhmmss/`. Backup logs are sent to `$DMK_HOME/log/backup/backup_<instance_name>_YYYYMMDD_hhmmss.log`.

***

#### Notes

* Ensure the MongoDB instance is reachable and running before performing a backup.
* For replica sets, it is generally recommended to perform backups from a secondary node to avoid impacting the primary.


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