Symantec Operating Corporation

Veritas Operating Corporation

Radha Shelat

Dilip Madhusudan Ranade

Navin Kabra

Anindya Banerjee

Sivaramakrishna Ramadugu Venkata

BijayaLaxmi Nanda

Laxmikant Vithal Gunda

A plurality of data objects may be replicated across a plurality of computing nodes coupled to a network. The network may include a first node operable to initiate an update operation to update a plurality of replicas of a first object. If one or more of the replicas are not reachable then the update operation may update a subset (e.g., a quorum) but not all of the replicas. For each node on which one of the replicas was updated in the update operation, the node may add the object to a list of incoherent objects. The list of incoherent objects may subsequently be used to bring the lagging replicas in sync with the replicas that were updated. In another embodiment, a plurality of replicas of an object may be stored on a plurality of nodes, similarly as described above. A first node that stores a replica of the object may store a first timestamp associated with the replica on the first node. The timestamp may be used to ensure that the replica on the first node is coherent with respect to one or more other replicas by periodically communicating with the one or more other replicas when a threshold amount of time has passed without the replica on the first node receiving an update.

Coherency of replicas for a distributed file sharing system

A system and method for adaptively responding to update messages for a replica of a data object. A node may maintain first information regarding a replica of a data object. In various embodiments, the first information may comprise any kind of information regarding the replica of the data object. In one embodiment, the first information may comprise information indicative of accesses to the replica of the data object, e.g., may comprise access history information. In response to receiving a message for updating the replica of the data object, the node may respond to the message based on the first information. For example, the node may select one or more operations to perform based on the first information and may perform the one or more selected operations.

Adaptive caching for a distributed file sharing system

A system including a plurality of nodes operable to exchange information using location-independent addresses. According to one embodiment of a method for obtaining information in a network of nodes, one or more nodes may each create an instance of a location-independent address A. The location-independent address A may represent an address for sending request messages (also referred to simply as requests) in order to obtain information or data from the one or more nodes with which the location-independent address A is associated (i.e., from the one or more nodes that create instances of the location-independent address A). According to one embodiment of a method for storing information in a network of nodes, one or more nodes may each create an instance of a location-independent address A, similarly as described above. However, instead of representing an address for sending requests to obtain information or data, in this case the location-independent address A may represent an address for sending requests to store information or data.

Global monitoring and statistics collection for a plurality of computing nodes

A system for fault tolerant multi-stage data replication with relaxed coherency comprises one or more processors and memory coupled to the processors, where the memory stores program instructions executable by the processors to implement a data replication service. In response to an update request directed at a data object, in a first stage of replication, the data replication service is configured to update respective primary replicas at a plurality of primary replica sites for the data object, and to store metadata descriptors at each of the plurality of primary replica sites. The data replication service is configured to determine whether a notification of the update is to be sent to any other replica sites. In response to identifying such other replica sites, an update notification including contents of a metadata descriptor may be sent to the other replica sites in one or more additional replication stages.

Fault tolerant multi-stage data replication with relaxed coherency guarantees

A method, system, and computer program product are provided to synchronize data maintained in separate storage areas using a copy-on-read technique. The separate storage areas may be distributed across a network, and the replicas of the data may be used for backup and/or disaster recovery purposes. Storage objects containing data and information relevant to managing the data by a particular application are identified, and only those storage objects are read. Data contained in the storage objects read are then copied to the replica storage area. This process avoids reading non-useful data, making the synchronization more efficient and conserving bandwidth of connections over which the data are sent.

Growing community of inventors

Pune, India

Radha Shelat