Backups
P4 Code Review stores all of the information it requires to operate within the P4 Server. This 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 recommendations 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 in P4 Server Administration Documentation.
In addition, your P4 Code Review configuration and any modifications you might make to the provided modules, templates, CSS, JavaScript, etc. also need to be backed up. The SWARM_ROOT/data directory contains the configuration, as well as temporary working files and browser session storage.