Setting Nonvolatile Storage Off for the Subsystem

SETCACHE NVS OFF deactivates the NVS. This command also disconnects the NVS battery on a 3990 Model 6, or 9390, or on a 3990 Model 3 with either RPQ 8B0174 or 8B0175 installed. DASD fast write is stopped and all modified DASD fast write data is destaged to the appropriate volumes. Cache fast write data is not destaged. Dual copy changed cylinder logging is terminated for dual copy volumes, but both copies of dual copy volumes continue to be updated.

Either a hardware failure in a duplex pair while the NVS is deactivated, or a utility power outage, or a loss of cache, or the cache being set off at this time causes all duplex pairs to be set to suspended duplex state at the next write I/O to each pair.