Provided are a computer program product, system, and method demote scan processing to demote tracks from cache. Tracks in the storage stored in the cache are indicated in a cache list. The cache list is scanned to determine unmodified tracks to initiate to demote. In response to processing an indicated modified track in the cache list while scanning the cache list, a destage is initiated for the processed indicated modified track and continuing to scan the cache list to determine unmodified tracks. In response to processing a number of modified tracks indicted in the cache list, a determination is made of an unmodified track in the cache list and continuing to scan, from the determined unmodified track, for unmodified tracks to initiate to demote.

Processing of prefetched data based on cache residency. Data to be used in future processing is prefetched. A block of data being prefetched is selected for processing, and a check is made as to whether the block of data is resident in a selected cache (e.g., L1 cache). If the block of data is resident in the selected cache, it is processed; otherwise, processing is bypassed until a later time when it is resident in the selected cache.

A storage system maintains a cache and a non-volatile storage. An error recovery component queries a cache component to determine whether modified customer data exists in a memory preserve cache. In response to determining that the modified customer data exists in the memory preserve cache, and in response to a failure beyond a threshold number of times of initial microcode load (IML) attempts to recover the modified customer data, an error notification is transmitted for manual intervention to avoid loss of the modified customer data.

The disclosure of the present invention presents a method and system for efficiently maintaining an object cache to a maximum size by number of entries, whilst providing a means of automatically removing cache entries when the cache attempts to grow beyond its maximum size. The method for choosing which entries should be removed provides for a balance between least recently used and least frequently used policies. A flush operation is invoked only when the cache size grows beyond the maximum size and removes a fixed percentage of entries in one pass.

The present disclosure includes memory having a static cache and a dynamic cache. A number of embodiments include a memory, wherein the memory includes a first portion configured to operate as a static single level cell (SLC) cache and a second portion configured to operate as a dynamic SLC cache when the entire first portion of the memory has data stored therein.

In accordance with one implementation, a method for reducing cache service time includes determining an access time parameter associated with movement of a read/write head to an access location for each of a plurality of contiguous cache storage segments and dynamically selecting one of the plurality of contiguous cache storage segments to store data based on the determined access time parameter.

Systems and methods provide a storage controller with write-back caching capabilities that may be used during scenarios where the storage controller is required to provide write-through caching, and thus unable to utilize internal cache memory for write-back caching. The storage controller utilizes an allocation of persistent memory that is made available by the host IHS (Information Handling System), to which the storage controller is coupled. In scenarios where the storage controller is required to provide write-through caching, the storage controller may be configured to route received write data to the allocated host memory. In this manner, the data integrity provided by write-through operations is maintained, while also providing the host IHS with the speed of write-back operations. When ready to store the write data, the storage controller may request the flushing of write data from the allocated host memory.

Processing prefetch memory operations and transactions. A local processor receives a prefetch request from a remote processor. Prior to execution of the prefetch request, determining whether a priority of the remote processor is greater than a priority of a local processor. The write prefetch request is executed in response to a to a determination that the priority of the remote processor is greater than the priority of the local processor. Prefetch data produced by execution of the prefetch request is provided to the remote processor.

In one aspect, performance optimization for data persistency in asynchronous replication setups includes creating at a source site of a data replication system, a snapshot (snapshot N) of input/output (IO) requests as part of a replication cycle, computing a delta of snapshot N and a previously created snapshot (snapshot N1), and transmitting the delta to a target site of the data replication storage system. An aspect further includes storing, at the target site, snapshot N1 during transmission of the delta, and caching the delta to a non-persistent storage device. Upon determining an occurrence of a loss event at the target site, a further aspect includes transmitting, by the target site, a request to retransmit the delta, retransmitting, by the source site, the delta to the target site, caching the delta to the non-persistent storage device until successful transmission of the delta, and committing the transmitted delta to permanent storage.

A SSD caching system for hybrid storages is disclosed. The caching system for hybrid storages includes: a Solid State Drive (SSD) for storing cached data, separated into a Repeated Pattern Cache (RPC) area and a Dynamical Replaceable Cache (DRC) area; and a caching managing module, including: an Input/output (I/O) profiling unit, for detecting I/O requests for accesses of blocks in a Hard Disk Drive (HDD) during a number of continuously detecting time intervals, and storing first data corresponding to first blocks being repeatedly accessed at least twice in individual continuously detecting time intervals to the RPC area sequentially; and a hot data searching unit, for detecting I/O requests for accesses of a HDD during a independently detecting time interval, and storing second data corresponding to second blocks being accessed at least twice in the independently detecting time interval to the DRC area sequentially.