A method of caching data is performed by a respective computer having one or more processors storing one or more storage management programs for execution by the one or more processors, non-volatile secondary storage and non-volatile cache memory. The method includes receiving from the non-volatile cache memory information identifying an amount of available storage in the non-volatile cache memory, and identifying a size of the management units in the non-volatile cache memory. The method further includes identifying write requests to write data to the non-volatile cache memory, sequentially writing to the non-volatile cache memory the write data for the identified write requests, to sequentially arranged locations in an address space of the non-volatile cache memory, and storing in memory metadata that maps the addresses or storage offsets of the write data to respective locations in the address space of the non-volatile cache memory.

Cache management including solid state device virtualization

Embodiments of the systems and methods disclosed provide a distributed RAID system comprising a set of data banks. More particularly, in certain embodiments of a distributed RAID system each data bank has a set of associated storage media and executes a similar distributed RAID application. The distributed RAID applications on each of the data banks coordinate among themselves to distribute and control data flow associated with implementing a level of RAID in conjunction with a volume stored on the associated storage media of the data banks. Migration of volumes, or portions thereof, from one configuration to another configuration may be accomplished according to a priority associated with the volume.

Method and System for Rebuilding Data in a Distributed RAID System

A processing device receives a message encapsulating an input/output (I/O) command from a remote computing device. The processing device identifies one or more physical storage devices to be accessed to satisfy the I/O command. The processing device then sends, to each physical storage device of the one or more physical storage devices, one or more non-volatile memory express (NVMe) commands directed to that physical storage device.

Non-volatile memory express over ethernet

A hybrid storage system is described having a mixture of different types of storage devices comprising rotational drives, flash devices, SDRAM, and SRAM. The rotational drives are used as the main storage, providing lowest cost per unit of storage memory. Flash memory is used as a higher-level cache for rotational drives. Methods for managing multiple levels of cache for this storage system is provided having a very fast Level 1 cache which consists of volatile memory (SRAM or SDRAM), and a non-volatile Level 2 cache using an array of flash devices. It describes a method of distributing the data across the rotational drives to make caching more efficient. It also describes efficient techniques for flushing data from L1 cache and L2 cache to the rotational drives, taking advantage of concurrent flash devices operations, concurrent rotational drive operations, and maximizing sequential access types in the rotational drives rather than random accesses which are relatively slower. Methods provided here may be extended for systems that have more than two cache levels.

Multi-leveled cache management in a hybrid storage system

Techniques are provided for using an intermediate cache to provide some of the items involved in a scan operation, while other items involved in the scan operation are provided from primary storage. Techniques are also provided for determining whether to service an I/O request for an item with a copy of the item that resides in the intermediate cache based on factors such as a) an identity of the user for whom the I/O request was submitted, b) an identity of a service that submitted the I/O request, c) an indication of a consumer group to which the I/O request maps, or d) whether the intermediate cache is overloaded. Techniques are also provided for determining whether to store items in an intermediate cache in response to the items being retrieved, based on logical characteristics associated with the requests that retrieve the items.

Selectively reading data from cache and primary storage

An apparatus, system, and method are disclosed for redundant write caching. The apparatus, system, and method are provided with a plurality of modules including a write request module, a first cache write module, a second cache write module, and a trim module. The write request module detects a write request to store data on a storage device. The first cache write module writes data of the write request to a first cache. The second cache write module writes the data to a second cache. The trim module trims the data from one of the first cache and the second cache in response to an indicator that the storage device stores the data. The data remains available in the other of the first cache and the second cache to service read requests.

David Flynn

Papers

Apparatus, system, and method for redundant write caching