Netapp, Inc.

Emc Corporation

Network Appliance, Inc.

Epoch Systems, Inc.

David Noveck

Sairam Veeraswamy

Daniel Alan Muntz

Michael Kazar

Richard Parvin Jernigan, Iv

Robert Wyckoff Hyer, Jr

Peter Griess

Toby Smith

Peter Frank Corbett

Mark Muhlestein

Ravi Wijayaratne

Thomas Haynes

Thomas J Dwyer, Iii

Alex Burlyga

Raymond C Chen

John Russell Boyles

John J Wallace

Benjamin T H Cox

Described are techniques for creating a snapshot of a distributed file system or a file thereof. The distributed file system includes metadata file systems storing metadata about files in the distributed file system and includes data file systems storing file content data. Quiescing is performed for requests affecting the distributed file system, or a file thereof, for which a snapshot is being created. A snapshot of metadata is obtained. For the distributed file system, this includes a snapshot of each metadata file system. For a file, this includes a snapshot of the file's metadata. A snapshot of file data is obtained. For distributed file systems, this includes a snapshot of each data file system. For a file, this includes a snapshot of the file's data. Unquiescing is performed for requests affecting the distributed file system, or the file thereof, upon successful completion of obtaining snapshots of metadata and file data.

Distributed file system having separate data and metadata and providing a consistent snapshot thereof

A method is presented for operating a filesystem. The method includes (a) storing data of the filesystem in a data storage filesystem (DSFS) in block-addressable non-volatile storage and (b) storing metadata of the filesystem in a metadata filesystem (MDFS) separate from the DSFS, at least a portion of the metadata being stored in word-addressable memory (WAM) having a persistence feature. Several embodiments are described for achieving this, using, for example, only non-volatile WAM, while other embodiments are described using, for example, a combination of volatile WAM and persistence techniques, while yet other embodiments are described using, for example, a combination of persistence-enhanced WAM and data storage.

Techniques for storing metadata of a filesystem in persistent memory

Read delay or write delay is added to server computers of a geographically distributed data processing system so that when writing to a dataset occurs at a first server and reading from the dataset occurs at a second server, the sum of any delay of returning an acknowledgement of completion of each write request and any delay in the reading of data for each read request is at least the data transmission delay between the two servers. For certain client applications such as NFS, the added delay is sufficient to compensate for the transmission delay without the use of a conventional read lock, which would require a round-trip delay. The method can provide an up-to-date global view of the dataset at each of the servers. The method can also provide equal performance of read access and write access at each of the servers.

Introduction of read delay or write delay in servers of a geographically distributed data processing system so that clients read up-to-date data

Described are techniques for performing quota management in a distributed file system. An allocation quota specifies an upper limit of storage for allocation for a quota set of the distributed file system. The distributed file system includes metadata file system(s) and data file system(s). For files in the distributed file system, metadata is stored in one of the metadata file systems and file content data is stored in the data file systems. A quota coordinator partitions the allocation quota among the data file systems. The data file systems are allocators of storage and each receives a portion of the allocation quota specifying an upper limit of storage that the data file system has available for allocation for the quota set. Storage is allocated for client requests. The storage allocation is performed by each of the data file systems in accordance with the portion of the allocation quota assigned.

Providing file system quota support for a file system having separated data and metadata

A storage system, such as a file server, uses pathname aliasing and exports a stored resource to clients by advertising to the clients a different pathname than the actual pathname of the resource.

Aliasing of exported paths in a storage system

Providing file sytem quota support for a file system having separated data and metadata

A system and method integrates a persistent reply cache with operation of a file system executing on a storage system. In an illustrative embodiment, the persistent reply cache is embodied as a file comprising a combination of contents of (i) one or more enhanced non-volatile log records of non-volatile electronic storage, (ii) 'dirty' in-core buffer cache data structures, and (iii) on-disk data structures corresponding to those dirty buffer cache data structures. Integration is achieved through atomic operation of the reply cache with the file system to store information associated with a reply, e.g., to a client request, on electronic storage implemented as in-core buffer cache memory of the storage system, as well as on magnetic storage implemented as disks of the system.

Persistent reply cache integrated with file system

Apparatus and method are disclosed for managing lock state information in a distributed file system. A set of data containers storing data is maintained. The data containers are striped across a plurality of volumes, where each volume includes one or more data storage devices. A metadata volume is maintained with the plurality of volumes, the metadata volume configured to include a lock state database that stores lock state information for the plurality of volumes. The lock state information is communicated between the metadata volume and the plurality of volumes.

System and method for managing hard lock state information in a distributed storage system environment

A method for managing locking requests for a computer file is disclosed. A plurality of locks is maintained for the file, the plurality of locks having locks of different types. Constraints are tracked on the plurality of locks of different types. A request for a requested lock is received. A determination is made if the requested lock violates any of the constraints on the plurality of locks. The requested lock is granted if there is no violation of any constraint on any of the plurality of locks. The requested lock is denied if the requested lock violates any constraint on any of the plurality of locks. An action disposition set having bit positions which define each lock of the plurality of locks is maintained. Bit-wise logic using the action disposition set determines if a requested lock violates any constraint on any of the plurality of locks.

Multi-protocol lock manager

A system and method manages lock state information in a storage system. A meta-data volume node includes a lock state database which is a comprehensive source for lock state information about data containers in the system. A plurality of data volume nodes include local lock caches, which contain information about locks. Lock state messaging between the meta-data volume node and the data volume nodes is used to assign locks and to update local lock caches. The meta-data volume node is configured to determine whether input/output requests should be allowed or denied and to instruct the data volume nodes of this input/output operation result. Lock information is also sent to the data volume nodes for storage in local lock state caches to the extent the data volume nodes have the network capacity locally.

System and method for managing hard and soft lock state information in a distributed storage system environment

A system and method to make file handles opaque to other network devices is provided. The system and method encrypts a file handle after it is generated and returns the encrypted file handle to a requesting client. The system and method may also generate a hash table storing hash key, a copy of the encrypted file handle and a copy of the unencrypted file handle. Upon a later receipt of an encrypted file handle, the system and method may hash the encrypted file handle to identify an appropriate hash table entry and it's associated unencrypted hash key. Alternately, the system may decrypt every received encrypted file handle and not utilize a hash table.

System and method to make file handles opaque to clients

A system and method manages lock state information in a distributed file system. A meta-data volume includes a lock state database which is a comprehensive source for lock state information about a striped volume set in the system. A plurality of data volumes includes local lock caches which contain information about locks. Lock state messaging between the meta-data volume and the data volumes is used to assign locks and to update local lock caches. The meta-data volume is configured to assigned permissive areas in the data containers accessed by clients in order to efficiently manage the lock state information.

A multi-protocol lock manager efficiently manages granting, revoking and releasing of various types of locks on files or regions of files located on a file server, such as a filer. The various locks are associated with multiple different file access protocols, each having its own semantics. The multi-protocol lock manager allows the filer to take appropriate actions with respect to locking requests and other file access operations, while ensuring that the actions taken are always consistent with semantic requirements for each lock, as established by the associated file access protocol.

Growing community of inventors

Lexington, MA, United States of America

David Noveck