Decrypt InnoDB Redo Logs

Steps to decrypt InnoDB redo logs by setting `innodb_redo_log_encrypt=OFF` and restarting the server to generate plaintext logs.

When data-at-rest encryption is enabled in MariaDB Enterprise Server, InnoDB can encrypt redo logs. If you later disable encryption or need to recover data from encrypted redo logs, you may need to decrypt the redo log files before MariaDB can process them.

For more information, refer to MDEV-17270.

1. Stop MariaDB Enterprise Server

   sudo systemctl stop mariadb

2. Locate the redo log files By default, InnoDB redo log files are stored in the data directory, typically as:

   ib_logfile0
   ib_logfile1

   or in the #innodb_redo directory for MariaDB versions using the new redo log format.

3. Prepare configuration for decryption

   • Make sure innodb_redo_log_encrypt is set to ON (to ensure the redo logs are recognized as encrypted).

   • Ensure that the key management plugin (such as file_key_management or aws_key_management) is configured exactly as it was when the redo logs were created.

   Example:

   [mysqld]
   plugin_load_add = file_key_management
   file_key_management_filename = /etc/mysql/encryption/keyfile.enc
   file_key_management_filekey = FILE:/etc/mysql/encryption/keyfile.key
   innodb_redo_log_encrypt = ON

4. Start MariaDB with decryption enabled

   • Start the server normally. MariaDB will automatically attempt to decrypt redo logs at startup using the configured key management plugin.

   • If successful, the redo logs are decrypted on-the-fly and crash recovery proceeds.

   sudo systemctl start mariadb

5. Disable redo log encryption if no longer required After recovery or once you confirm that decrypted redo logs are no longer needed, you can disable redo log encryption in the configuration:

   [mysqld]
   innodb_redo_log_encrypt = OFF

   Then restart the server. New redo logs will be created in plaintext.

Verification

You can verify the redo log encryption status with:

SHOW GLOBAL VARIABLES LIKE 'innodb_redo_log_encrypt';

Example output:

+------------------------+-------+
| Variable_name          | Value |
+------------------------+-------+
| innodb_redo_log_encrypt| OFF   |
+------------------------+-------+