Symantec Corporation

Veritas Technologies LLC

Sushil Sarjerao Patil

Sanjay Kumar Jain

Kedar Shrikrishna Patwardhan

Anindya Banerjee

Shirish Vijayvargiya

Neha Naik

Sanjay Kumar

Mukesh Sohanlal Bafna

Freddy James

Anirban Mukherjee

Mithlesh Thukral

Suprio Das

Rachit Chadha

Ramprasad Chinthekindi

Various systems and methods use advisory metadata to track the status of file system objects. For example, one method can involve accessing a first item of advisory metadata, which is associated with a namespace-visible parent directory and identifies a first transaction and a first time, and accessing a second item of advisory metadata, which is also associated with the namespace-visible parent directory and identifies a second transaction and a second time. The namespace visible parent directory includes multiple namespace-hidden directories. The method can then select a time value of the advisory metadata for the namespace-visible parent directory, based upon the first item and the second item. The method can be performed by a computing device implementing a file system.

Timestamp handling for partitioned directories

A computer-implemented method for mitigating write-back caching failures may include (1) detecting a failure that impairs at least one write-back cache that temporarily caches updates for individual files stored on a storage device, (2) identifying an attribute of an individual file stored on the storage device in response to the failure that impairs the write-back cache, (3) determining that at least a portion of the individual file is obsolete based at least in part on the attribute of the individual file, and then (4) performing at least one mitigating action with respect to the individual file to address the obsolete portion of the individual file. Various other methods, systems, and computer-readable media are also disclosed.

Systems and methods for mitigating write-back caching failures

Caching metadata that identify hot blocks at a per local cache level are tracked. Tracked caching metadata are maintained so as to be persistent and shared across nodes of the cluster. Local caches are pre-warmed by using maintained caching metadata, responsive to detecting specific node level events. Such events can result in hot blocks being absent from a local cache, such as a failover between nodes or an unexpected failure local to a specific node. Another event example is the access of shared storage content, such as opening a file or mounting a file system by a specific node, in response to which the associated local cache can be pre-warmed using the tracked caching metadata for the specific file, or for each file of the file system. To pre-warm a local cache, hot blocks of stored content identified by corresponding caching metadata are loaded into the local cache.

Local cache pre-warming

A computer-implemented method for securing storage space may include 1) identifying a block map that indicates whether each of a plurality of blocks within a storage system is to return zeroed data in response to read operations, 2) identifying a read operation directed to a block of the storage system that includes non-zeroed data, 3) determining, in response to identifying the read operation, that the block map indicates that the block is to return zeroed data in response to the read operation, and 4) returning zeroed data in response to the read operation based on determining that the block map indicates that the block is to return zeroed data. Various other methods, systems, and computer-readable media are also described.

Systems and methods for securing storage space

A system and method for migrating file systems is provided. A file system migration operation copies a plurality of files from a first file system to a second file system. A request to access one of the files being migrated during the file system migration operation results in the creation of a pseudo vnode for the file being requested in the second file system. The pseudo vnode is created prior to creating a vnode for the file in the second file system. In addition, the pseudo vnode is associated with a vnode of the file at the first file system. Information identifying the pseudo vnode is then returned to the application.

Lookup optimization during online file system migration

A method for file lock recovery in a distributed computer system. The method includes executing a distributed computer system having a plurality of nodes comprising a cluster, and initiating a network file system server migration from one node of the cluster to a different node of the cluster. A migration count is incremented, wherein the migration count is stored at each of the nodes comprising the cluster. File lock services are paused at each of the nodes comprising the cluster. The network file system server migration is completed at the different node of the cluster. The migration count is then decremented in response to the completion. File lock services are then resumed at each of the nodes comprising cluster.

Method and system for performing a clean file lock recovery during a network filesystem server migration or failover

Techniques for optimizing data migration are disclosed. In one particular embodiment, the techniques may be realized as a method for optimizing data migration may comprise receiving a request for initiating a data migration application and migrating, via at least one computer processor, at least one data file from a migration list during the data migration application. The method for optimizing data migration may also comprise monitoring the migration of the at least one data file and determining whether the at least one data file is active during the migration of the at least one data file. The method for optimizing data migration may further comprise deferring the migration of the at least one data file based at least in part on a determination that the at least one data file is active and recording information associated with the at least one data file if the at least one data file is active.

Growing community of inventors

Kolhapur, India

Sushil Sarjerao Patil