Emc Corporation

Digital Equipment Corporation

Other

Emc IP Holding Company LLC

Peter C Bixby

Sorin Faibish

John Forecast

Wayne William Duso

Sairam Veeraswamy

Xiaoye Jiang

Uday K Gupta

Daniel Gardere

Stephen A Fridella

Jiannan Zheng

Michel Noury

Philippe Armangau

Jean-Pierre Bono

Walter A O'Brien, Iii

Donald F Hooper

Peter W Madany

Hongliang Tang

Sachin Mullick

Jeffrey S Kenny

Seyfullah H Oguz

Matthew S Goldman

Suban Krishnamoorthy

Curtis Herron

Ben Davis

Percy Tzelnic

Sitaram D Pawar

Morgan A Clark

Christopher H Stacey

Marc DeSouter

Pranit Sethi

William C Whitney

Ugur Sezer

Sebastian Keller

Jean Louis Rochette

William O Hultin

Raymond Mantchala

An end cap for a panel support of a panel assembly comprising an exposed surface and a side surface. The exposed surface of the end cap has opposing edges, and the exposed surface forms a selected end effect. The side surface has at least one fastener hole. The edges of the exposed surface of the end cap are configured to mate with an end surface of the panel support.

Panel assembly

An aluminum interconnecting panel support has an insertion end with an inserting member for insertion into another support of a panel assembly. The interconnecting panel support includes a visible portion that is visible to human perception upon interconnecting the support within the panel assembly. The panel support also has a hidden portion that is hidden from perception upon interconnecting the support within the panel assembly. The panel support has a rectilinear body portion connected to the insertion end that spans a length of the support. The panel support has a curved support member that is disposed at a normal to the body portion. The visible portion of the panel support as assembled in the panel assembly includes the body portion. The hidden portion includes the curved support member, fasteners, or both. The curved support member adjoins additional panel members to previously assembled panel members, and it supports the body portion.

Large files in a file system are mapped by extents of contiguous indirect blocks in order to reduce the time for read or write access to the large files while allowing allocation of data blocks one at a time. The inode of a file includes an indication of whether file mapping metadata of the file includes either an extent of contiguous indirect blocks or a tree of blocks. In a preferred mapping scheme, an inode contains an array of block pointer entries, and each entry includes a flag indicating whether the block pointer is pointing to either an extent of indirect blocks or a tree of blocks. For sharing of data blocks between files, the block pointer fields of the indirect blocks each contain an ownership flag indicating whether the pointed-to block is shared or not.

Using extents of indirect blocks for file mapping of large files

A file server system having solid-state drive primary storage and magnetic disk drive secondary storage aggressively moves newly created files from the primary storage to selected file systems in the secondary storage to match expected access patterns upon the files to different configurations of the file systems and for load balancing upon the file systems in the secondary storage. Upon read access to a file that has been moved to the secondary storage, or upon migration of a newly created file that was read in primary storage after creation, a corresponding stub file containing file mapping metadata is created in the primary storage. The file mapping metadata in the stub file maps the extent of the file to logical storage addresses in the secondary storage.

File server system having tiered storage including solid-state drive primary storage and magnetic disk drive secondary storage

A dataset is recovered after a server reboot while clients access the dataset. In response to the reboot, not-yet-completed transactions in a log are parsed to create, for each of the dataset blocks modified by these active transactions, a respective block replay list of the active transactions that modify the block. Once the block replay lists have been created, clients may access specified blocks of the dataset after on-demand recovery of the specified blocks. The on-demand recovery is concurrent with a background recovery task that replays the replay lists. To accelerate log space recovery, the parsing of the log inserts each replay list into a first-in first-out queue serviced by multiple replay threads. The queue can also be used as the cache writeback queue, so that the cache index is used for lookup of the replay list and the recovery state of a given block.

Multi-threaded in-memory processing of a transaction log for concurrent access to data during log replay

A dataset is concurrently recovered after a server crash while the dataset is actively used for servicing client requests. In response to a reboot, records of not-yet-completed transactions in a transaction log are parsed to create a graph of dependencies between the transactions. Once this graph has been created, clients may access a specified block of the dataset after on-demand recovery of the specified block. The on-demand recovery is concurrent with a background recovery task that replays the not-yet-completed transactions in time order. The on-demand recovery uses the dependency graph to replay any and all transactions that support recovery of the specified block, so that recovery of the specified block includes update of other blocks to be consistent with the recovered block in accordance with the not-yet-completed transactions.

Concurrent access to data during replay of a transaction log

To preserve the contiguity of file map extents of a production file when making a series of snapshot copies, the snapshots share indirect blocks of the production file through virtual pointers. When a write to a data block of the production file is first done since the time of the most recent snapshot so that the most recent snapshot can no longer share one of the contiguous indirect blocks, a new indirect block is allocated to store the file mapping metadata for the most recent snapshot, and a virtual pointer for the snapshots is changed to point to this new indirect block. Therefore the change in the virtual pointer changes the file mapping metadata for any number of snapshots sharing the new indirect block so that the method is scalable.

Creating point-in-time copies of file maps for multiple versions of a production file to preserve file map allocations for the production file

Based on a count of the number of dirty pages in a cache memory, the dirty pages are written from the cache memory to a storage array at a rate having a component proportional to the rate of change in the number of dirty pages in the cache memory. For example, a desired flush rate is computed by adding a first term to a second term. The first term is proportional to the rate of change in the number of dirty pages in the cache memory, and the second term is proportional to the number of dirty pages in the cache memory. The rate component has a smoothing effect on incoming I/O bursts and permits cache flushing to occur at a higher rate closer to the maximum storage array throughput without a significant detrimental impact on client application performance.

Rate proportional cache write-back in a storage server

Embodiments of the invention relate to maintaining reference counts in a file system to track when a block is available to be freed. When a snapshot copy of a file is created, rather than copying all the blocks of the file for the snapshot copy, the snapshot inode is given pointers to the blocks of the file. Rather than updating the reference counts for all these blocks to indicate that they are now in use by more than one file, the update of reference counts for at least some of these blocks may be deferred until a later time.

Methods and apparatus for creating a branch file in a file system

Servers in a storage system store a nested multilayer directory structure, and a global index that is an abstract of the directory structure. The global index identifies respective portions of the directory structure that are stored in respective ones of the servers, and the global index identifies paths through the directory structure linking the respective portions. Upon performing a top-down search of the directory structure in response to a client request and finding that a portion of it is offline, the global index is searched to discover portions of the directory structure that are located below the offline portion. The global index may also identify the respective server storing each of the respective portions of the directory structure, and may indicate whether or not each of the respective portions of the directory structure is known to be offline.

Pathname caching and protection of the root directory in a nested multilayer directory structure

Methods and apparatus for creating point in time copies in a file system using reference counts

A method is used in managing metadata. Data of an object is stored in a magnetic hard disk set in an object addressable data storage system. Metadata for the object is stored in an SSD set in the object addressable data storage system. The metadata includes information necessary for determining the location of the data of the object in the magnetic hard disk set.

Managing metadata

A file server includes active storage containing frequently accessed files, and active/inactive disk drives for containing infrequently accessed files. Groups of the files having become inactive in the active storage are successively migrated to respective evacuated active/inactive disk drives so that each active/inactive disk drive is loaded with files having a similar probability of access when access to the active/inactive disk drive reaches an inactivity threshold for powering down the active/inactive disk drive. Storage of the active/inactive disk drives is reclaimed when an oldest group of the files is archived or when an active/inactive disk drive is evacuated by migrating files from the active/inactive disk drive to storage having been released in other disk drives by promotion of files for client access to the promoted files. Therefore, recovery of storage can be planned and scheduled in advance and performed efficiently in a background process.

Intelligent file system based power management for shared storage that migrates groups of files based on inactivity threshold

A write interface in a file server provides permission management for concurrent access to data blocks of a file, ensures correct use and update of indirect blocks in a tree of the file, preallocates file blocks when the file is extended, solves access conflicts for concurrent reads and writes to the same block, and permits the use of pipelined processors. For example, a write operation includes obtaining a per file allocation mutex (mutually exclusive lock), preallocating a metadata block, releasing the allocation mutex, issuing an asynchronous write request for writing to the file, waiting for the asynchronous write request to complete, obtaining the allocation mutex, committing the preallocated metadata block, and releasing the allocation mutex. Since no locks are held during the writing of data to the on-disk storage and this data write takes the majority of the time, the method enhances concurrency while maintaining data integrity.

Multi-threaded write interface and methods for increasing the single file read and write throughput of a file server

Growing community of inventors

Westborough, MA, United States of America

Peter C Bixby