Additional uncaught exception thrown while handling exception.

Original

RedisException: READONLY You can't write against a read only slave. in Redis->hSet() (line 39 of /var/www/drupal/sites/all/modules/contrib/redis/lib/Redis/Path/PhpRedis.php).

Additional

RedisException: READONLY You can't write against a read only slave. in Redis->exec() (line 103 of /var/www/drupal/sites/all/modules/contrib/redis/lib/Redis/Cache/PhpRedis.php).