According to an example, data corruption and single point of failure is prevented in a fault-tolerant memory fabric with multiple redundancy controllers by granting, by a parity media controller, a lock of a stripe to a redundancy controller to perform a sequence on the stripe. The lock may be broken in response to determining a failure of the redundancy controller prior to completing the sequence. In response to breaking the lock, the parity cacheline of the stripe may be flagged as invalid. Also, a journal may be updated to document the breaking of the lock.