Emc IP Holding Company LLC

Paul A Shelley

Steven Richard Bromling

Joshua Baergen

Victor Salamon

Ronald C Unrau

A cache coherency protection system provides for data redundancy by sharing a cache coherence memory pool for protection purposes. The system works consistently across all communication protocols, yields improved data availability with potentially less memory waster and makes data availability faster in node/director failure scenarios. According to various embodiments, the cache coherency protection system may include a writer/requester director that receives a write request from host, a protection target director that is a partner of the writer/request director and a directory.

Cache protection through cache

An apparatus in one embodiment comprises a storage system including a plurality of storage nodes each associated with one or more storage devices. The storage system is configured to provide at least one virtual volume distributed over the storage nodes for utilization by a plurality of host devices. The storage nodes comprise respective input-output sequencers for handling input-output operations directed to the distributed virtual volume by the host devices. The input-output sequencers of the respective storage nodes are configured to interact with one another to collectively form a distributed input-output sequencer that ensures consistency across the storage nodes for the distributed virtual volume when accessed by different ones of the host devices. The storage system may comprise a multi-site storage system, with the plurality of storage nodes comprising at least a first storage node cluster at a first site and a second storage node cluster at a second site.

Storage system with distributed input-output sequencing

An apparatus in one embodiment comprises a storage system including a plurality of storage nodes each associated with one or more storage devices. The storage system is configured to provide at least one virtual volume distributed over the storage nodes for utilization by a plurality of host devices. The storage nodes are configured to support selection between multiple operating modes for handling input-output operations directed to the distributed virtual volume by the host devices. The multiple operating modes comprise at least a cached mode of operation in which consistency across the storage nodes for the distributed virtual volume when accessed by different ones of the host devices is ensured utilizing a distributed cache coherence protocol implemented by cooperative interaction of cache controllers of respective ones of the storage nodes, and a cacheless mode of operation in which consistency is ensured without utilizing the distributed cache coherence protocol and its associated cache controllers.

Growing community of inventors

Edmonton, Canada

Paul A Shelley