Emc IP Holding Company LLC

Bruce A Pocock

Douglas Eric LeCrone

Paul A Linstead

Jeffrey L Jones

A host computing system includes an applications layer containing one or more user applications that perform I/O operations, an access methods layer that communicates with the applications layer, an I/O drivers layer that communicates with the access methods layer, and an SSCH simulation layer that communicates with the I/O drivers layer and that simulates a Fibre Channel connection that is accessed by applications in the applications layer. The host computing system may also include a TCP/IP stack layer that communicates with the SSCH simulation layer to provide TCP/IP communication for the host computing system. TCP/IP communication provided by the TCP/IP stack layer may be separate from any dedicated TCP/IP communication provided by the host. The host computing system may be coupled to a TCP/IP network. A cloud storage may be coupled to the network to communicate with the host computing system.

Simulation for alternative communication

Causing an application on a host to access a point-in-time image on a storage system includes the application generating concurrent copy commands that are designed to cause data to be copied from a first location to a second location independent of whether the data is accessed by the host following initiating creation of a concurrent copy, intercepting concurrent copy commands and data generated by the application prior to sending the commands and data from the host to the storage system, transforming the concurrent copy commands and data to revised commands and data that are used to access the point-in-time image. Transforming the concurrent copy commands may include allocating temporary space on the storage system. The revised commands and data are sent from the host to the storage system. All commands generated by the application may be intercepted by the drivers layer. Only concurrent copy commands may be transformed.

Concurrent copy emulation

A host coupled to a storage system accesses secondary storage coupled to the storage system and to the host by determining if direct data access between the storage system and the secondary storage is operational, the host forwarding commands to the storage system to directly access the secondary storage in response to direct data access between the storage system and the secondary storage being operational, and the host generating modified commands to cause the host to directly access the secondary storage in response to direct data access between the storage system and the secondary storage not being operational. The secondary storage may be a cloud storage. The secondary storage may be a tape emulation unit. The host may directly access data of the tape emulation unit by accessing a storage device of the tape emulation unit. Commands on the host may be modified by a drivers layer on the host.

Accessing secondary storage

Transferring data from a storage device to cloud service includes initiating a snapshot of the data, accessing each block of the data corresponding to the snapshot to transfer each block to the cloud service, and terminating the snapshot after all of the blocks have been transferred to the cloud service. At least some blocks of the storage device that are modified after initiating the snapshot may be copied from the storage device to a storage pool prior to modification. Only a first modification of a particular one of the blocks of the storage device may cause the particular one of the blocks to be copied to the storage pool. Accessing each block of the data may include accessing blocks of the storage pool. Modifying a particular one of the blocks of the storage device may include modifying a corresponding block of a storage pool.

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Hoschton, GA, United States of America

Bruce A Pocock