Maintaining write cache and parity update footprint coherency in multiple storage adaptor configuration

A computer program product 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, the computer program product comprising:

• a non-transitory computer usable medium having computer usable program code embodied therewith, the computer usable program code comprising:
• instructions to create a device correlation data for the storage device based on a first one of the storage adaptors, and to store 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
• instructions to increase, upon detection of a failure of a second one of the storage adaptors, 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 to repeat 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.

A computer system, comprising:

• a processor;
• a memory operatively coupled with the processor;
• a storage device operatively coupled with the processor and the memory;
• and
• a computer program product 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, the computer program product comprising:
• a non-transitory computer usable medium having computer usable program code embodied therewith, the computer usable program code comprising:
• instructions to create a device correlation data for the storage device based on a first one of the storage adaptors, and to store 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
• instructions to increase, upon detection of a failure of a second one of the storage adaptors, 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 to repeat 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.