A processor corresponding to a core of a coprocessor, a cache used as a buffer of the processor, and a flash controller are connected to an interconnect network. The flash controller and a flash memory are connected to a flash network. The flash controller reads or writes target data of a memory request from or to the flash memory.

A method for demoting data from a cache comprising heterogeneous memory types is disclosed. The method maintains, for a data element in the cache, a write access count that is incremented each time the data element is updated in the cache. The cache includes a higher performance portion and a lower performance portion. The method removes the data element from the higher performance portion in accordance with a cache demotion algorithm. If the data element also resides in the lower performance portion and the write access count is below a first threshold, the method leaves the data element in the lower performance portion. If the data element also resides in the lower performance portion and the write access count is at or above the first threshold, the method removes the data element from the lower performance portion. A corresponding system and computer program product are also disclosed.

One embodiment provides a system for facilitating data placement. The system receives a sector of data to be written to a first non-volatile memory and a second non-volatile memory, wherein the first non-volatile memory resides on a first storage device which supports sequential writes, and wherein the second non-volatile memory resides on a second storage device. The system writes the sector and its corresponding logical block address to the first non-volatile memory in a sequential manner. The system writes, at approximately a same time, the sector and its corresponding logical block address to the second non-volatile memory. In response to completing the write to the first non-volatile memory or the second non-volatile memory, the system generates an acknowledgment that the sector is successfully committed for a host from which the sector is received.

Various embodiments described herein provide for a memory sub-system read operation or a memory sub-system write operation that can be requested by a host system and involves performing a multi-level (e.g., two-level) pointer dereferencing internally within the memory sub-system. Such embodiments can at least reduce the number of read operations that a host system sends to a memory sub-system to perform a multi-level dereferencing operation.

A storage system has priority queues for real time-class file system messaging and backup-class file system messaging. The storage system includes servers, coupled as a storage cluster, storage devices and a network coupling the servers and the storage devices. The servers have priority queues. The servers operate the priority queues for messaging from the servers to the storage devices via the network in accordance with a real time-class file system and a backup-class file system. A first subset of the priority queues has higher priority on the network for real time-class file system messaging of at least one type. A second subset of the priority queues has lower priority on the network for backup-class file system messaging of at least one type.

A method for demoting data from a cache comprising heterogeneous memory types is disclosed. The method maintains for a data element in the cache, a write access count that is incremented each time the data element is updated in the cache. The cache includes a higher performance portion and a lower performance portion. The method also maintains, for the data element, a read access count that is incremented each time a data element is read in the cache. The method removes the data element from the higher performance portion of the cache in accordance with a cache demotion algorithm. If the write access count is below a first threshold and the read access count is above a second threshold, the method places the data element in the lower performance portion. A corresponding system and computer program product are also disclosed.

In certain aspects, one or more solid-state storage devices (SSDs) are provided that include a controller and non-volatile memory coupled to the controller. The non-volatile memory can include one or more portions configured as main memory or cache memory. When data stored in the main memory is written to the cache memory for processing, the data in the main memory is erased. In certain aspects, storage systems are provided that include one or more of such SSDs coupled to a host system. In certain aspects, methods are provided that include: receiving, by a first such SSD, a first command to write data to memory; determining that the data is stored in a main memory and is to be written to the cache memory for processing; writing the data to the cache memory; and erasing the data from the main memory.

To improve performance of a storage system. The storage system includes a plurality of storage nodes that communicate via a network. Each of the plurality of storage nodes includes one or more controllers. At least one controller in the controllers specifies at least two controllers that allocate a cache sub-area where write data is stored based on a controller that receives the write data from a host and a controller that processes the write date, and the cache sub-area is allocated in the specified controllers.

In a storage system that implements metadata paging, the page free pool is replenished in the background to reduce foreground evictions and associated latency on page-in. A two-level page eviction controller with cascaded proportional, integral, derivative (PID) controllers optimizes the size of the free page pool and optimizes the rate at which pages are freed in the background. By optimizing these two parameters the page eviction controller dynamically maximizes used pages (minimizing free pages) to increase the metadata cache hit ratio. Optimizing the parameters also reduces the chances of foreground page evictions, thereby reducing IO latency, during both steady state and burst page-in requests.

A storage control device includes: an auxiliary cache memory that is a nonvolatile memory; a volatile memory; and a processor configured to execute a saving control process after a predetermined failure occurs, the saving control process being configured to (a) cause a writing control process to stop writing of data stored in the auxiliary cache memory to the storage medium, (b) secure, in the auxiliary cache memory, a storage region for storing the management information of the volatile memory, (c) generate a copy of management information of the volatile memory in the storage region, and (d) cause the writing control process to execute control to write first data stored in the volatile memory to the auxiliary cache memory or the storage medium based on the management information of the auxiliary cache memory.