An internal spa filter for a spa, having a filter body with an inlet opening at its one end and a discharge orifice at its opposite end, the sides of such body are formed with auxiliary spa water inlet openings. When the active server A101 or the active disk 113 fails, the administration server 106 chooses a backup server A104 and a status storage disk A114 to be booted and restarts them by using the snapshot according to the policy. The resultant of this combination is used as the key to the cryptographic engine.