# Operating `hi`

## Upgrades

`hi` will automatically upgrade its database on startup. Before doing so, it will create a backup of your database (at `.hi.backup`, or controlled by `--backup-database-url`). If the migration process succeeds, this backup will be deleted automatically. If the migration process _fails_, however, the backup will be left in place. In addition, `hi` will attempt to restore your existing database from the backup before exiting.

`hi` will not start if the backup database already exists. To restart `hi` after a failure, move the backup database aside. Once you are satisfied that `hi` has recovered successfully, you can delete it. If you need to restore the database manually, you can also copy it overtop of your database using normal filesystem tools (`cp -a .hi.backup. hi`, for example).