The overall steps for how Encryption at Rest is enabled and used in the DR Series system are described below.

1. Enabling encryption.

   Encryption is disabled by default on a factory-installed DR Series system (running version 3.2 software or later) or a DR Series system that has been upgraded to version 3.2 from a previously released version. An administrator can enable encryption by using the GUI or CLI.

   Encryption is set at the storage group level.

2. Setting a passphrase and setting the mode.

   When defining encryption for a storage group, a passphrase is set. This passphrase is used to encrypt the content encryption keys, which adds a second layer of security to the key management. At this time, the mode is also set. The default key management mode is “internal” mode, in which key rotation happens periodically as specified by the set key rotation period.

3. Encryption process.

   After encryption is enabled, the data in the storage group that gets backed up is encrypted and is kept encrypted until it is expired and cleaned by the system cleaner. Note that the encryption process is irreversible.

4. Encryption of pre-existing data.

   Any pre-existing data will also be encrypted using the currently set mode of key management. This encryption occurs as part of the system cleaner process. Encryption is scheduled as the last action item in the cleaner workflow. You must launch the cleaner manually using the maintenance command to reclaim space. It then encrypts all pre-existing unencrypted data. The cleaner can also be scheduled as per the existing pre-defined cleaner schedule.

   NOTE: The cleaner can take some time to start the encryption process if the system is nearing full system capacity. Encryption starts only after the cleaner processes data slated for cleaning and the related logs. This ensures that space reclamation is prioritized when free space is low and also ensures that data stores are not redundantly encrypted.