How are mail account backups handled on cPanel mail node servers?
What happens if either of my servers crash, the Web server or Mail node server, and I need to restore?
You can configure the backups for the accounts and where these backups will be stored on the server. You can also configure additional destinations for off-site backups through the WHM.
Account and System Files Backup Configuration
Account backups do store the email on the parent server where backups are configured.
For restoring the accounts, you first need to relink the servers in their child and parent roles and then restore the account. Restore an account from a backup file on the server