A disk-less quorum device in a clustered storage system includes non-volatile memory to store status information regarding the cluster and each storage controller in the cluster. The quorum device maintains a bitmap, shared by the controllers in the cluster, in the non-volatile memory. The bitmap indicates the status of a write operation to any data block or parity block. A “dirty” data unit in the bitmap indicates that a write operation has been submitted but is not yet finished. Upon submitting a write request (to update a data block or a parity block) to the storage facility, a controller sets the corresponding data unit “dirty” in the bitmap. After receiving an acknowledgement from the storage facility indicating that the operation has been completed, the controller clears the corresponding data unit. If a controller fails during a write operation, another controller can use the bitmap to re-establish data consistency.