In response to receiving a read request for target data, an external address of the target data is obtained from the read request, which is an address unmapped to a storage system; hit information of the target data in cache of the storage system is determined based on the external address; and based on the hit information, an address from the external address and an internal address for providing the target data is determined. The internal address is determined based on the external address and a mapping relationship. Therefore, it can shorten the data access path, accelerate the responding speed for the data access request, and allow the cache to prefetch the data more efficiently.

Data is stored at a cache portion of a cache memory of a memory sub-system responsive to a request to perform a write operation to write the data. A duplicate copy of the data is stored at a write buffer portion of the cache memory. The cache memory is partitioned into the cache portion and the write buffer portion. An entry that maps a location of the duplicate copy of the data stored at the write buffer portion of the cache memory to a location of the data stored at the cache portion of the cache memory is recorded in a write buffer record.

A method for maintaining statistics for data elements in a cache is disclosed. The method maintains a heterogeneous cache comprising a higher performance portion and a lower performance portion. The method maintains, within the lower performance portion, a ghost cache containing statistics for data elements that are currently contained in the heterogeneous cache, and data elements that have been demoted from the heterogeneous cache within a specified time interval. The method calculates a size of the ghost cache based on an amount of frequently accessed data that is stored in backend storage volumes behind the heterogeneous cache. The method alters the size of the ghost cache as the amount of frequently accessed data changes. A corresponding system and computer program product are also disclosed.

A data storage system provides persistent storage in bulk non-volatile memory. A controller of the data storage system receives a host write command and buffers associated host write data in both a first write cache in non-volatile memory and a mirrored second write cache in volatile memory. The controller destages the host write data to the bulk non-volatile memory from the second write cache but not the first write cache. The controller services relocation write commands requesting data relocation within the bulk non-volatile memory by reference to the second write cache. Servicing the relocation write commands includes buffering relocation write data in the second write cache but not the first write cache and destaging the relocation write data to the bulk non-volatile memory from the second write cache.

A storage system includes a CPU, a first memory module, a second memory module, and a storage device. The processor and the first memory module are installed in the same node. The second memory module are replaceable without shutting down power supply of the node. The first memory module stores an operating system and a program for managing user data to be stored in the storage device. The second memory module stores cache data of the user data to be stored in the storage device. The processor is configured to store a copy of data to be stored in the second memory module in the third memory module.

A method, computer program product, and computing system for receiving, via a storage processor of a storage system, a write request for writing a data portion to a storage array enclosure of non-volatile memory express (NVMe) drives communicatively coupled to the storage processor, where the write request may be received from a host. The data portion may be written to a persistent memory write cache within the storage array enclosure.

Systems and processes are disclosed to preserve data integrity during a storage controller failure. In some examples, a storage controller of an active-active controller configuration can back-up data and corresponding cache elements to allow a surviving controller to construct a correct state of a failed controller's write cache. To accomplish this, the systems and processes can implement a relative time stamp for the cache elements that allow the backed-up data to be merged on a block-by-block basis.

Techniques for managing a storage system involve: based on a degree of importance of data stored in a persistent storage device of the storage system, determining key data from the data, wherein a degree of importance of the key data is higher than a threshold degree; respectively identifying first data corresponding to the key data in a first cache of the storage system and second data corresponding to the key data in a second cache of the storage system as non-removable; and in response to corruption of the first data, repairing the first data using the second data in the second cache. Such techniques can avoid system shutdown caused by corruption of key data.

The role of a node component of a distributed application may be changed without the need to terminate a current OS process implementing the node component. A first component on a first node of a distributed file server may be designated as a control path master and configured to execute a first group of services defined for the control path master as part of a first OS process. One or more other components on one or more other nodes of the distributed file server may be designated as a control path agent and configured to execute a second group of services defined for the control path agent as part of a respective second OS process. The control path master may be changed to a control path agent, and a control path agent may be changed to a control path master, without having to reboot the control path component in question.

Provided are a computer program product, system, and method for indicating extents of tracks in mirroring queues based on information gathered on tracks in extents in cache. Extent information on an extent of tracks in a cache indicated in an active cache list is processed in response to destaging a track from the active cache list to add to a demote list used to determine tracks to remove from the cache. The extent information is related to a number of modified tracks in an extent destaged from the active cache list. The extent information for the extent is used to determine one of a plurality of mirroring queues to indicate the extent including modified tracks. A mirroring queue having a higher priority than another mirroring queue is processed at a higher rate to determine extents of tracks to mirror from the cache to the secondary storage.