Maintaining a synchronous replication relationship between two or more storage systems, including: receiving, by at least one of a plurality of storage systems across which a dataset will be synchronously replicated, timing information for at least one of the plurality of storage systems; and establishing, based on the timing information, a synchronous replication lease describing a period of time during which the synchronous replication relationship is valid, wherein a request to modify the dataset may only be acknowledged after a copy of the dataset has been modified on each of the storage systems.

Provided are an electronic system of a real-time operating system, an operating method thereof, and an operating method for a memory device. The operating method comprising obtaining a call graph by performing static code analysis on at least one thread that corresponds to a task, obtaining a stack usage of the thread and a call probability for each node by performing runtime profiling of the call graph, allocating a threshold value of a stack size for a first memory area by taking into account the call graph, the call probability for each node, and the stack usage, expanding and storing a stack from the first memory area to a second memory area according to a comparison result between the threshold value and a stack usage of the first memory area and returning the stack to the first memory when execution is completed in the second memory area, wherein the electronic system comprises a memory device configured to include the first memory area and the second memory area.

Managing storage systems that are synchronously replicating a dataset, including: detecting a change in membership to the set of storage systems synchronously replicating the dataset; and applying one or more membership protocols to determine a new set of storage systems to synchronously replicate the dataset, wherein the one or more membership protocols include a quorum protocol, an external management protocol, or a racing protocol, and wherein one or more I/O operations directed to the dataset are applied to a new set of storage systems.

Managing connectivity to synchronously replicated storage systems, including: identifying a plurality of storage systems across which a dataset is synchronously replicated; identifying a host that can issue I/O operations directed to the dataset; identifying a plurality of data communications paths between the host and the plurality of storage systems across which a dataset is synchronously replicated; identifying, from amongst the plurality of data communications paths between the host and the plurality of storage systems across which a dataset is synchronously replicated, one or more optimal paths; and issuing, to the host, an identification of the one or more optimal paths.

Provided are a computer program product, integrated cache manager, and method for maintaining data in a first level memory and buckets representing regions of memory devices to extend data cache. A plurality of buckets represent distinct regions of memory devices. The buckets are associated with different threshold access count ranges. Data having an access count is stored in one of the buckets associated with a threshold access count range including the access count of the data to store. Data evicted from a first level memory is copied to an initial bucket comprising one of the buckets. Data is moved from a source bucket comprising one of the buckets, including the initial bucket, to a target bucket of the buckets having a target threshold access count range including an access count of the data to move.

Systems and methods for garbage collection are disclosed. A garbage collection is triggered in a memory allocation based on a free list and selected amount of free space in an inner closed feedback loop. The free list is determined from a selected memory load and a current memory load as generated from the garbage collection in an outer feedback loop.

Resilient mediation between storage systems replicating a dataset, including: receiving, by a mediation service from one or more storage systems that synchronously replicate a dataset, a request to resolve which storage system continues to service a dataset after the request; and sending, from the mediation service to at least one of the storage systems, a positive mediation result, wherein: the storage systems that received the positive mediation result continue to process data storage requests directed to the dataset, and the storage systems that did not receive a positive mediation result from the mediation service do not continue to process data storage requests directed to the dataset.

Synchronizing metadata among storage systems synchronously replicating a dataset, where synchronizing the metadata includes: receiving, at a first storage system of the storage systems, an I/O operation directed to the dataset; determining, in dependence upon the I/O operation, a metadata update describing a mapping of segments of content to a virtual address within a storage object, wherein the storage object includes the dataset; and synchronizing metadata on a second storage system of the storage systems by sending the metadata update to the second storage system to update a metadata representation on the second storage system in accordance with the metadata update.

Managing connectivity to synchronously replicated storage systems, including: identifying a plurality of storage systems across which a dataset is synchronously replicated; identifying a host that can issue I/O operations directed to the dataset; identifying a plurality of data communications paths between the host and the plurality of storage systems across which a dataset is synchronously replicated; identifying, from amongst the plurality of data communications paths between the host and the plurality of storage systems across which a dataset is synchronously replicated, one or more optimal paths; and issuing, to the host, an identification of the one or more optimal paths.

A read cache management method and apparatus based on a solid state drive, and the method includes: determining whether a read request hits a first queue and a second queue (S101); if both the first queue and the second queue are missed, selecting and deleting an eliminated data block from the first queue (S102); if the eliminated data block is in a stored state, inserting the eliminated data block into the second queue (S103); and determining a target data block in a lower-level storage medium, and inserting the target data block into the first queue, (S104). According to the foregoing read cache management method and apparatus based on the solid state drive, a hit ratio of the solid state drive can be increased, a data write count of the solid state drive can be reduced, and service life of the solid state drive can be extended.