Abstract: A dual cluster storage server maintains track control blocks (TCBs) in a data structure to describe the data stored in cache in corresponding track images or segments. Following a cluster failure and reboot, the surviving cluster uses the TCBs to rebuild data structures such as a scatter table, which is a hash table that identifies a location of a track image, and a least recently used (LRU)/most recently used (MRU) list for the track images. This allows the cache data to be recovered. The TCBs describe whether the data in the track images is modified and valid, and describe forward and backward pointers for the data in the LRU/MRU lists. A separate non-volatile memory that is updated as the track images are updated is used to verify the integrity of the TCBs.

Abstract: A storage system, method of managing a storage system and program product for managing a storage system. Cache fast write (CFW) modified data may be provided to cache in count-key-data (CKD) tracks with associated meta data. A synchronization flag is included on a storage device with associated meta data for each CKD track stored. The cache directory control block (CDCB) includes a CDCB synchronization flag for each CKD track in cache memory. A mismatch in the synchronization flags from a failure during a transfer to storage indicates a storage device loss of synchronization between an accessed CKD track and stored associated meta data.

Abstract: An apparatus and a method to allocate device adapter bandwidth, where that device adapter is disposed in an information storage and retrieval system capable of communicating with one or more host computers, and where that device adapter interconnects a data cache with information storage devices. The data storage and retrieval system receives a plurality of requests from the host computers to read information from, or to write information to, information storage devices. The method determines a read/write request ratio and a non-volatile storage utilization ratio. The method allocates device adapter bandwidth based upon the read/write request ratio and/or the non-volatile storage utilization ratio.

Abstract: A storage system, method of managing a storage system and program product for managing a storage system. Cache fast write (CFW) modified data may be provided to cache in count-key-data (CKD) tracks with associated meta data. A synchronization flag is included on a storage device with associated meta data for each CKD track stored. The cache directory control block (CDCB) includes a CDCB synchronization flag for each CKD track in cache memory. A mismatch in the synchronization flags from a failure during a transfer to storage indicates a storage device loss of synchronization between an accessed CKD track and stored associated meta data.