A PGP Encryption Server Ignition Key protects certain data by encrypting it (Symantec Encryption Management Server).
This protects the data in the unlikely event that an unauthorized person obtained control of the database.
After the administrator successfully logs into the PGP Encryption Server they are prompted for the ignition key passphrase. They are only prompted for the ignition key passphrase after each reboot of the server (simulating someone having access to the physical machine).
If a server is rebooted but the administrator does not enter the passphrase to the Ignition Key, the server will still replicate data with other cluster members if it is part of a cluster. Ignition keys are a good method to protection of data on the server from direct access. For more information on Ignition Keys, reach out to Symantec Encryption Support.