Abstract: A network storage server system includes a presentation layer that presents multiple namespaces over the same data stored in an object store, allowing users to simultaneously access data over multiple protocols. The system supports object location independence of the stored data objects by introducing a layer of indirection between directory entries and storage locations of stored data objects. In one embodiment, the directory entry of a data object points to a redirector file that includes an object locator (e.g., an object handle or a global object ID) of the data object. The directory entries of data objects are stored in a directory namespace (e.g., NAS path namespace). In another embodiment, a global object ID of the data object is directly encoded within the directory entry of the data object.

Abstract: Deduplication of data using a low-latency random read memory (LLRRM) is described herein. Upon receiving a block, if a matching block stored on a disk device is found, the received block is deduplicated by producing an index to the address location of the matching block. In some embodiments, a matching block having a predetermined threshold number of associated indexes that reference the matching block is transferred to LLRRM, the threshold number being one or greater. Associated indexes may be modified to reflect the new address location in LLRRM. Deduplication may be performed using a mapping mechanism containing mappings of deduplicated blocks to matching blocks, the mappings being used for performing read requests. Deduplication described herein may reduce read latency as LLRRM has relatively low latency in performing random read requests relative to disk devices.

Abstract: Deduplication of data using a low-latency random read memory (LLRRM) is described herein. Upon receiving a block, if a matching block stored on a disk device is found, the received block is deduplicated by producing an index to the address location of the matching block. In some embodiments, a matching block having a predetermined threshold number of associated indexes that reference the matching block is transferred to LLRRM, the threshold number being one or greater. Associated indexes may be modified to reflect the new address location in LLRRM. Deduplication may be performed using a mapping mechanism containing mappings of deduplicated blocks to matching blocks, the mappings being used for performing read requests. Deduplication described herein may reduce read latency as LLRRM has relatively low latency in performing random read requests relative to disk devices.

Abstract: A method implements a cache-policy switching module in a storage system. The storage system includes a cache memory to cache storage data. The cache memory uses a first cache configuration. The cache-policy switching module emulates the caching of the storage data with a plurality of cache configurations. Upon a determination that one of the plurality of cache configurations performs better than the first cache configuration, the cache-policy switching module automatically applies the better performing cache configuration to the cache memory for caching the storage data.

Abstract: Fault isolation capabilities made available by user space can be provided for a embedded network storage system without sacrificing efficiency. By giving user space processes direct access to specific devices (e.g., network interface cards and storage adapters), processes in a user space can initiate Input/Output requests without issuing system calls (and entering kernel mode). The multiple user spaces processes can initiate requests serviced by a user space device driver by sharing a read-only address space that maps the entire physical memory one-to-one. In addition, a user space process can initiate communication with another user space process by use of transmit and receive queues similar to transmit and receiver queues used by hardware devices. And, a mechanism of ensuring that virtual addresses that work in one address space reference the same physical page in another address space is used.

Abstract: Deduplication of data on disk devices based on a threshold number (THN) of sequential blocks is described herein, the threshold number being two or greater. Deduplication may be performed when a series of THN or more received blocks (THN series) match a sequence of THN or more stored blocks (THN sequence), whereby a sequence comprises blocks stored on the same track of a disk device. Deduplication may be performed using a block-comparison mechanism comprising metadata entries of stored blocks and a mapping mechanism containing mappings of deduplicated blocks to their matching blocks. The mapping mechanism may be used to perform later read requests received for the deduplicated blocks. The deduplication described herein may reduce the read latency as the number of seeks between tracks may be reduced. Also, when a seek to a different track is performed, the seek time cost is spread over THN or more blocks.