Emc IP Holding Company LLC

Netapp, Inc.

Emc Corporation

John F Gillono

Philippe Armangau

Christopher Alan Seibel

Andy Kahn

Edward Ramon Zayas

Thomas Haynes

Vamsi K Vankamamidi

Yubing Wang

Bruce E Caram

Maher Kachmar

Sreelatha Sunkara Reddy

Sorin Faibish

Jean-Pierre Bono

Ashok Tamilarasan

Sitaram D Pawar

Srinivasa Rao Vempati

Alexei Karaban

Diane Delgado

Lawrence Yetto

Jason C Penney

A method of managing CPU cores in a data storage apparatus (DSA) configured to perform both host I/O (Input/Output) processing and background storage processing is provided. The method includes (a) selectively classifying background storage tasks in one of a first classification for longer-running tasks and a second classification for shorter-running tasks; (b) selecting CPU cores that are running fewer than a threshold number of first-classification background tasks to process host I/O requests; and (c) processing the host I/O requests on their selected CPU cores. An apparatus, system, and computer program product for performing a similar method are also provided.

Techniques for managing cores for storage

A method, computer program product, and computer system for receiving an indication about an amount of background IOs a background scheduler is capable of performing on a plurality of applications, wherein the indication may be based upon, at least in part, one of host IO latency and a rate of the host IO latency being at one of a plurality of levels. One or more applications of the plurality of applications on which to perform the background IOs may be determined. The background IO applications to be performed on the one or more applications of the plurality of applications may be scheduled based upon, at least in part, one of the host IO latency and the rate of the host IO latency being at one of the plurality of levels.

System and method for priority orchestration and scheduling of different background operations

Embodiments are directed to techniques for performing deduplication. A method includes (a) obtaining a digest of a data block logically-positioned within a filesystem, the digest providing a hash value of data of the data block, (b) searching a Most Wanted Digest Cache (MWDC) within system memory for the digest, (c) locating an entry in the MWDC using the digest, wherein this locating indicates that the data block has the same data as another data block located elsewhere within the filesystem, the other data block having been previously persistently-stored, the entry having been added to the MWDC in response to the other data block having been deduplicated at least a plurality number of times, (d) locating a mapping structure referenced by the entry located from the MWDC, the mapping structure providing metadata about the other data block, and (e) deduplicating the data block and the other data block with reference to the located mapping structure.

Speeding deduplication using a most wanted digest cache

A technique for managing metadata in a data storage system includes receiving a set of data to be stored in a file system of the data storage system and calculating values of metadata blocks that the file system will use to organize the set of data in the file system. The technique aggregates values of the metadata blocks and sends them in a single, atomic transaction to a persistent cache. The transaction either succeeds, in which case the persistent cache stores the values of all of the metadata blocks, or it fails, in which case the persistent cache stores none of the values of the metadata blocks. Over time, the persistent cache flushes the values of the metadata blocks to a set of non-volatile storage devices that back the metadata blocks in the data storage system.

Managing file system metadata using persistent cache

A technique for storing data in a data storage system detects that a read is being performed pursuant to a data copy request. In response, the data storage system stores a digest of the data being read in an entry of a digest cache. Later, when a write pursuant to the same copy request arrives, the storage system obtains the entry from the digest cache and completes the write request without creating a duplicate copy of the data.

Optimizing inline deduplication during copies

A method is used in managing copying of data in storage systems. A request is received to copy a portion of a source logical object to a target logical object. The source and target logical objects are subject to a deduplicating technique. The portion of the source logical object is copied to the target logical object by updating metadata of the target logical object. The target logical object shares the portion of the source logical object.

Managing copying of data in storage systems

A method is used in managing caches in storage systems. A set of block entries is reserved in a reserved block entries list of a storage system. The reserved block entries list is associated with a cache of the storage system configured to store data of the storage system. A portion of a memory of the storage system is reserved as the cache. Based on a criterion, a determination is made whether a cache entry is available for use in the cache of the storage system. Based on the determination, a block entry is selected for use from the reserved block entries list.

Managing caches in storage systems

A system and method verifies and restores the consistency of inode to pathname mappings. In a first embodiment, an off-line verification procedure is modified to verify and correct the primary name inode to pathname mapping information within inodes of a file system. In a second embodiment, an on-line file system verification process is modified to verify inode to pathname mapping information upon the loading of each inode within the file system.

System and method for verifying and restoring the consistency of inode to pathname mappings in a filesystem

A system and method maintains mappings from data containers to their parent directories within a file system of a storage system. Each inode is modified to include a primary name data structure comprising a parent directory inode and a parent directory cookie value. The parent directory cookie value identifies a particular directory entry within a specified block of a directory identified by parent directory inode. An alternate name file is utilized to store alternate names, such as those associated with hard links.

System and method for maintaining mappings from data containers to their parent directories

A method is used in recovering in deduplication systems. Metadata of a data object is evaluated for determining deduplication status for the data object. Based on the deduplication status, the data object is recovered.

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Methuen, MA, United States of America

John F Gillono