Abstract: Network data storage systems and methods allow computers reading and writing data at a plurality of data centers separated by, potentially, large distances to replicate data between sites such that the data is protected from failures, including complete Site failures, while not allowing network latency to significantly impede the performance of read or write operations. Continued access to all data is provided even after a single failure of any component of the system or after any complete failure of all equipment located at any single geographic region or any failure that isolates access to any single geographic region. Write data is replicated synchronously from Active Sites, e.g., sites where servers are writing data to storage resources, to Protection Sites located sufficiently close to Active Sites such that network latency will not significantly impact performance, but sufficiently far apart such that a regional disaster is unlikely to affect both sites.

Abstract: A plurality of access nodes sharing access to data on a storage network implement a directory based cache ownership scheme. One node, designated as a global coordinator, maintains a directory (e.g., table or other data structure) storing information about I/O operations by the access nodes. The other nodes send requests to the global coordinator when an I/O operation is to be performed on identified data. Ownership of that data in the directory is given to the first requesting node. Ownership may transfer to another node if the directory entry is unused or quiescent. The distributed directory-based cache coherency allows for reducing bandwidth requirements between geographically separated access nodes by allowing localized (cached) access to remote data.

Abstract: Storage virtualization systems and methods that allow customers to manage storage as a utility rather than as islands of storage which are independent of each other. A demand mapped virtual disk image of up to an arbitrarily large size is presented to a host system. The virtualization system allocates physical storage from a storage pool dynamically in response to host I/O requests, e.g., SCSI I/O requests, allowing for the amortization of storage resources-through a disk subsystem while maintaining coherency amongst I/O RAID traffic. In one embodiment, the virtualization functionality is implemented in a controller device, such as a controller card residing in a switch device or other network device, coupled to a storage system on a storage area network (SAN). The resulting virtual disk image that is observed by the host computer is larger than the amount of physical storage actually consumed.

Abstract: Storage virtualization systems and methods that allow customers to manage storage as a utility rather than as islands of storage which are independent of each other. A demand mapped virtual disk image of up to an arbitrarily large size is presented to a host system. The virtualization system allocates physical storage from a storage pool dynamically in response to host IO requests, e.g., SCSI I/O requests, allowing for the amortization of storage resources-through a disk subsystem while maintaining coherency amongst I/O RAID traffic. In one embodiment, the virtualization functionality is implemented in a controller device, such as a controller card residing in a switch device or other network device, coupled to a storage system on a storage area network (SAN). The resulting virtual disk image that is observed by the host computer is larger than the amount of physical storage actually consumed.

Abstract: Storage virtualization systems and methods that allow customers to manage storage as a utility rather than as islands of storage which are independent of each other. A demand mapped virtual disk image of up to an arbitrarily large size is presented to a host system. The virtualization system allocates physical storage from a storage pool dynamically in response to host I/O requests, e.g., SCSI I/O requests, allowing for the amortization of storage resources-through a disk subsystem while maintaining coherency amongst I/O RAID traffic. In one embodiment, the virtualization functionality is implemented in a controller device, such as a controller card residing in a switch device or other network device, coupled to a storage system on a storage area network (SAN). The resulting virtual disk image that is observed by the host computer is larger than the amount of physical storage actually consumed.

Abstract: Write order fidelity (WOF) is maintained for totally-active implementations wherein a plurality of access nodes at geographically separated sites can concurrently read and/or write data in a “totally active” fashion on a distributed data system. From the hosts' perspective at diverse geographic locations, a synchronous, cache-coherent view of data is provided. Data transfer is asynchronous. A time ordered data image is created and maintained so operations can be restarted after a partial system failure that causes loss of data not yet asynchronously transferred across the network, but that has been write-acknowledged to the originating host. Time ordered asynchronous data transfer is implemented as a pipeline of changes that reflect contributions from all nodes. WOF also improves network performance and lowers bandwidth consumption.

Abstract: Systems and methods for delivering streaming data content to a client device over a data communication network in response to a request for the data content from the client device. The client request is received by a server or a controller device that is typically located on a network switch device. If received by a server, the server sends a request to the controller device to control the transfer of the requested data to the client. The controller device includes the processing capability required for retrieving the streaming data and delivering the streaming data directly to the client device without involving the server system. In some cases, the controller device mirrors the data request to another controller device to handle the data processing and delivery functions. In other cases, the controller device coordinates the delivery of the requested data using one or more other similar controller devices in a pipelined fashion.

Abstract: Network data storage systems and methods allow computers reading and writing data at a plurality of data centers separated by, potentially, large distances to replicate data between sites such that the data is protected from failures, including complete Site failures, while not allowing network latency to significantly impede the performance of read or write operations. Continued access to all data is provided even after a single failure of any component of the system or after any complete failure of all equipment located at any single geographic region or any failure that isolates access to any single geographic region. Write data is replicated synchronously from Active Sites, e.g., sites where servers are writing data to storage resources, to Protection Sites located sufficiently close to Active Sites such that network latency will not significantly impact performance, but sufficiently far apart such that a regional disaster is unlikely to affect both sites.

Abstract: Write order fidelity (WOF) is maintained for totally-active implementations wherein a plurality of access nodes at geographically separated sites can concurrently read and/or write data in a “totally active” fashion on a distributed data system. From the hosts' perspective at diverse geographic locations, a synchronous, cache-coherent view of data is provided. Data transfer is asynchronous. A time ordered data image is created and maintained so operations can be restarted after a partial system failure that causes loss of data not yet asynchronously transferred across the network, but that has been write-acknowledged to the originating host. Time ordered asynchronous data transfer is implemented as a pipeline of changes that reflect contributions from all nodes. WOF also improves network performance and lowers bandwidth consumption.

Abstract: A plurality of access nodes sharing access to data on a storage network implement a directory based cache ownership scheme. One node, designated as a global coordinator, maintains a directory (e.g., table or other data structure) storing information about I/O operations by the access nodes. The other nodes send requests to the global coordinator when an I/O operation is to be performed on identified data. Ownership of that data in the directory is given to the first requesting node. Ownership may transfer to another node if the directory entry is unused or quiescent. The distributed directory-based cache coherency allows for reducing bandwidth requirements between geographically separated access nodes by allowing localized (cached) access to remote data.

Abstract: Storage virtualization systems and methods that allow customers to manage storage as a utility rather than as islands of storage which are independent of each other. A demand mapped virtual disk image of up to an arbitrarily large size is presented to a host system. The virtualization system allocates physical storage from a storage pool dynamically in response to host I/O requests, e.g., SCSI I/O requests, allowing for the amortization of storage resources-through a disk subsystem while maintaining coherency amongst I/O RAID traffic. In one embodiment, the virtualization functionality is implemented in a controller device, such as a controller card residing in a switch device or other network device, coupled to a storage system on a storage area network (SAN). The resulting virtual disk image that is observed by the host computer is larger than the amount of physical storage actually consumed.

Abstract: A server is embedded directly into a storage subsystem. When moving between the storage subsystem domain and the server domain, data copying is minimized. Data management functionality written for traditional servers is implemented within a stand-alone storage subsystem, generally without software changes to the ported subsystems. The hardware executing the storage subsystem and server subsystem can be implemented in a way that provides reduced latency, compared to traditional architectures, when communicating between the storage subsystem and the server subsystem. When using a plurality of clustered controllers, traditional load-balancing software can be used to provide scalability of server functions. One end-result is a storage system that provides a wide range of data management functionality, that supports a heterogeneous collection of clients, that can be quickly customized for specific applications, that easily leverages existing third party software, and that provides optimal performance.

Abstract: Storage virtualization systems and methods that allow customers to manage storage as a utility rather than as islands of storage which are independent of each other. A demand mapped virtual disk image of up to an arbitrarily large size is presented to a host system. The virtualization system allocates physical storage from a storage pool dynamically in response to host I/O requests, e.g., SCSI I/O requests, allowing for the amortization of storage resources through a disk subsystem while maintaining coherency amongst I/O RAID traffic. In one embodiment, the virtualization functionality is implemented in a controller device, such as a controller card residing in a switch device or other network device, coupled to a storage system on a storage area network (SAN). The resulting virtual disk image that is observed by the host computer is larger than the amount of physical storage actually consumed.

Abstract: Systems and methods for delivering electronic data storage to consumers in an efficient, cost-effective way. A new storage networking paradigm, Utility Storage, is provided which addresses the specific needs of SSPs. Many characteristics of the Utility Storage model enable a new SSP business model to be implemented that is more profitable and growth orientated. An SSP using the Utility Storage model is able to provides storage to an end customer with a low entry cost threshold that encourages incremental consumption by the consumer. Additionally, using the Utility Storage model, the SSP is able to provide storage services to an end customer at a lower cost by amortizing the operating and infrastructure costs across a larger population of customers.

Abstract: Storage virtualization systems and methods that allow customers to manage storage as a utility rather than as islands of storage which are independent of each other. A demand mapped virtual disk image of up to an arbitrarily large size is presented to a host system. The virtualization system allocates physical storage from a storage pool dynamically in response to host I/O requests, e.g., SCSI I/O requests, allowing for the amortization of storage resources through a disk subsystem while maintaining coherency amongst I/O RAID traffic. In one embodiment, the virtualization functionality is implemented in a controller device, such as a controller card residing in a switch device or other network device, coupled to a storage system on a storage area network (SAN). The resulting virtual disk image that is observed by the host computer is larger than the amount of physical storage actually consumed.