Abstract: Methods and system for implementing a clustered storage solution are provided. One embodiment is a storage controller that communicatively couples a host system with a storage device. The storage controller comprises an interface and a control unit. The interface is operable to communicate with the storage device. The control unit is operable to identify ownership information for a storage device, and to determine if the storage controller is authorized to access the storage device based on the ownership information. The storage controller is operable to indicate the existence of the storage device to the host system if the storage controller is authorized, and operable to hide the existence of the storage device from the host system if the storage controller is not authorized.

Abstract: Methods and structure for improved processing of fast path I/O requests in a clustered storage system. In a storage controller of a clustered storage system, the controller comprises a fast path I/O request processing circuit tightly coupled with host system drivers for fast processing of requests directed to storage devices of a logical volume. The controller also comprises a logical volume I/O processing stack (typically implemented as programmed instructions) for processing I/O requests from a host system directed to a logical volume. Based on detecting a change of ownership of a device or volume and/or a change to logical to physical mapping of a logical volume, fast path I/O requests may be converted to logical volume requests based on mapping context information within the fast path I/O request and shipped within the clustered storage system for processing.

Abstract: Methods and structure for improved buffer management in a storage controller. A plurality of processes in the controller each transmits buffer management requests to buffer management control logic. A plurality of reserved portions and a remaining non-reserved portion are defined in a shared pool memory managed by the buffer management control logic. Each reserved portion is defined as a corresponding minimum amount of memory of the shared pool. Each reserved portion is associated with a private pool identifier. Each allocation request from a client process supplies a private pool identifier for the associated buffer to be allocated. The buffer is allocated from the reserved portion if there sufficient available space in the reserved portion identified by the supplied private pool identifier. Otherwise, the buffer is allocated if sufficient memory is available in the non-reserved portion. Otherwise the request is queued for later re-processing.

Abstract: Methods and system for implementing a clustered storage solution are provided. One embodiment is a storage controller that communicatively couples a host system with a storage device. The storage controller comprises an interface and a control unit. The interface is operable to communicate with the storage device. The control unit is operable to identify ownership information for a storage device, and to determine if the storage controller is authorized to access the storage device based on the ownership information. The storage controller is operable to indicate the existence of the storage device to the host system if the storage controller is authorized, and operable to hide the existence of the storage device from the host system if the storage controller is not authorized.

Abstract: Methods and structure for improved shipping of I/O requests among multiple storage controllers of a clustered storage system. Minimal processing of a received I/O request is performed in a first controller to determine whether the I/O request is directed to a logical volume that is owned by the first controller or to a logical volume owned by another controller. For requests to logical volumes owned by another controller, the original I/O request is modified to indicate the target device address of the other controller. The first controller then ships the request to the other controller and configures DMA capabilities of the first controller to exchange data associated with the shipped request between the other controller and memory of the host system.

Abstract: Methods and system are provided for exposing logical volumes to host systems and storage controllers in a consistent manner across a clustered storage system. One embodiment is a storage controller. The storage controller is operable to communicate with other storage controllers within the clustered storage system. The storage controller is further operable to generate a proposed Logical Unit Number (LUN) for a logical volume provisioned at the storage devices, and to communicate with each of the other storage controllers within the clustered storage system requesting that the other storage controllers determine if the proposed LUN is in use. If the proposed LUN is not in use, then storage controller assigns the proposed LUN to the logical volume. If the LUN is in use, then the storage controller generates a new proposed LUN and re-tries communication with the other storage controllers until a unique LUN is found.

Abstract: A method for pricing a trade comprising providing a user input for entering trade data, providing a structure for receiving the trade data and then transmitting the structure to a pricing system. The structure, now populated with both the trade data and the pricing data, is received from the pricing system and the trade data and pricing information is displayed. Advantageously, the structure is encrypted prior to transmitting it to the pricing system and decrypted when received from the pricing system. The pricing system records the data and the pricing information, which may be automatically entered into a trading system if and when the user agrees.

Abstract: Apparatus and methods for improved region lock management in a storage controller. A region lock management circuit coupled with a memory is provided for integration in a storage controller. One or more I/O processor circuits of the storage controller transmit requests to the region lock management circuit to request a temporary lock for a region of storage on a volume of the storage system. The region lock management circuit determines whether the requested lock may be granted or whether it conflicts with other presently locked regions. Presently locked regions and regions to be locked are represented by region lock data structures. In one exemplary embodiment, the region lock data structures for each logical volume may be stored as a tree data structure. A tree assist circuit may also be provided to aid the region lock management circuit in managing the region lock tree data structures.

Abstract: A method for pricing a trade comprising providing a user input for entering trade data, providing a structure for receiving the trade data and then transmitting the structure to a pricing system. The structure, now populated with both the trade data and the pricing data, is received from the pricing system and the trade data and pricing information is displayed. Advantageously, the structure is encrypted prior to transmitting it to the pricing system and decrypted when received from the pricing system. The pricing system records the data and the pricing information, which may be automatically entered into a trading system if and when the user agrees.