1. A method for maintaining the coherency of a write cache, and that of a parity update footprint, of each of a plurality of storage adaptors connected to a storage device, comprising: creating a device correlation data for the storage device based on a first one of the storage adaptors, and storing the device correlation data on each of the storage adaptors and on the storage device, the device correlation data including a sequence number indicating a coherency status of the storage adaptors; and upon detection of a failure of a second one of the storage adaptors, increasing the sequence number of the device correlation data, stored on the storage device and on each of the storage adaptors other than the second storage adaptor, by one, and repeating the increasing a predetermined number of times, so as to atomically force the second storage adaptor out of synchronization, thereby maintaining the coherency of the write cache and of the parity update footprint of the other storage adaptors.