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Documentation | 2025.5

# Prepare for disaster recovery

Cyber attacks, natural disasters, power and network outages, and application failures can occur without warning, resulting in damage to systems and data. By having a plan for backup operations and disaster recovery, you can help your organization recover.

## Back up and recover installations

P4 Code Review stores all of the information it requires to operate within the P4 Server. This information includes project definitions, code reviews, comments, followers, and more. Code reviews are largely built on top of P4 Server's shelving feature, and most other records are stored in custom counters called keys.

Therefore, the standard guidelines for backing up your P4 Server also apply when backing up your P4 Code Review data. For more information about backup and recovery, see Backup and recovery.

The best way to recover a P4 Code Review installation is to reinstall the P4 Code Review package. For instructions, see Install and upgrade P4 Code Review.

## Back up and recover configurations

When you use the P4 Code Review user interface to configure projects, the information is stored in P4 Server and thus is backed up along with other P4 Server data. For more information, see Backup and recovery. Regularly test the backups for integrity to help ensure that the system can be restored after a disaster.

The P4 Code Review configuration and any modifications that you make to the provided modules, templates, CSS, and JavaScript also must be backed up. The `SWARM_ROOT/data` directory contains the configuration, as well as temporary working files and browser session storage.

Some of the P4 Code Review configuration information is stored in the `config.php` file, and there is no built-in backup process for this. You are responsible for the backup and recovery of this configuration file. For details, see “Swarm configuration file” in P4 Code Review configuration.

The configuration for related components is stored in the following configuration files:

- Redis configuration

- Apache configuration

- PHP configuration

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