Abstract: Systems and methods presented herein provide for region lock management in an expander. In one embodiment, an expander, being operable to link a plurality of initiators to a plurality of Redundant Array of Independent Disks logical volumes, includes a plurality of physical transceivers, each being operable to link the logical volumes to the initiators, and a region lock manager operable to receive a request from a first of the initiators to lock a region of the logical volumes for an input/output operation by the first initiator. The region lock manager is also operable to determine if the requested region is unlocked, to lock the requested region from the remaining initiators to allow the input/output operation of the first initiator after determining the requested region is unlocked, and to unlock the requested region after the input/output operation of the first initiator is complete.

Abstract: Methods and structure for coordinating between Redundant Array of Independent Disks (RAID) storage controllers are provided. An exemplary system includes a RAID controller. The RAID controller includes a Peripheral Component Interconnect Express (PCIe) interface, a Serial Attached Small Computer System Interface (SAS) port operable to communicate with another RAID controller, and a command unit. The command unit is able to direct the interface to contact another PCIe interface at the other controller, to acquire an identifier of the other controller stored in a PCIe Inbound Map (PIM) for the other interface, and to activate a feature for the controller that enables cooperative management of storage devices between the controller and the other controller, if the identifier of the other controller matches discovery information maintained at the controller.

Abstract: Systems and methods herein provide a storage system that optimizes the boot time when the storage system is rebooted. One embodiment includes a storage controller operable to determine a topology of one or more storage devices. The storage controller stores the topology in memory. When the storage controller detects a system reboot event, it provides the stored topology to the host and directs the host to reboot with the stored topology.

Abstract: Methods and structure for migrating logical volumes are provided. The system includes a Redundant Array of Independent Disks controller, which includes a Peripheral Component Interconnect Express interface, a Serial Attached Small Computer System Interface port operable to communicate with another Redundant Array of Independent Disks controller, and a command unit. The command unit is able to direct the interface to access another Peripheral Component Interconnect Express interface at the other controller, to synchronize with Disk Data Format information from a Peripheral Component Interconnect Express Inbound Map of the other interface, to detect that the other controller has failed, and to utilize the Disk Data Format information to migrate a logical volume from the other controller to the controller.

Abstract: Systems and methods presented herein provide for input/output shipping between storage controllers in a storage system. One storage system comprises a plurality of logical volumes, a host driver operable to process input/output requests to the logical volumes, and a plurality of storage controllers coupled between the server and the logical volumes. A first of storage controllers is operable to receive an input/output request from the host driver for one of the logical volumes, and transfer a command to a second of the storage controllers to retrieve the data of the input/output request. The second storage controller processes the command from the first storage controller, and retrieves the data associated with the input/output request.

Abstract: Methods and structure for coordinating between Redundant Array of Independent Disks (RAID) storage controllers are provided. An exemplary system includes a RAID controller. The RAID controller includes a Peripheral Component Interconnect Express (PCIe) interface, a Serial Attached Small Computer System Interface (SAS) port operable to communicate with another RAID controller, and a command unit. The command unit is able to direct the interface to contact another PCIe interface at the other controller, to acquire an identifier of the other controller stored in a PCIe Inbound Map (PIM) for the other interface, and to activate a feature for the controller that enables cooperative management of storage devices between the controller and the other controller, if the identifier of the other controller matches discovery information maintained at the controller.

Abstract: Methods and structure for migrating logical volumes are provided. The system includes a Redundant Array of Independent Disks controller, which includes a Peripheral Component Interconnect Express interface, a Serial Attached Small Computer System Interface port operable to communicate with another Redundant Array of Independent Disks controller, and a command unit. The command unit is able to direct the interface to access another Peripheral Component Interconnect Express interface at the other controller, to synchronize with Disk Data Format information from a Peripheral Component Interconnect Express Inbound Map of the other interface, to detect that the other controller has failed, and to utilize the Disk Data Format information to migrate a logical volume from the other controller to the controller.

Abstract: Methods and structure are provided for Serial Attached SCSI (SAS) expanders that program their own routing attributes. The structure includes a SAS expander comprising multiple physical links with associated transceivers (PHYs), wherein the PHYs are configured into ports at the expander, and a memory that defines routing attributes for each of the ports. The SAS expander also comprises a control unit that is operable to detect a discovery Serial Management Protocol (SMP) request received at a port of the expander, and that is further operable to set the routing attribute for the port to subtractive routing responsive to detecting the SMP request.

Abstract: A modified or host driver operable on a host computer communicates with a host interface of a PCIe adapter. A controller memory space is managed by the kernel space of the host operating system. The modified driver entirely avoids the overhead associated with making a copy from the application or user space to a separate kernel space managed by the operating system in the host computer. The modified driver uses a base address register to identify the location of the cache storage in the controller memory space. The size of the cache store is communicated to the modified driver upon a power on initialization of the PCIe adapter and the host computer. A memory map managed by the modified driver identifies cache storage locations as an offset from the base address register.

Abstract: An expander for a device architecture, such as a SAS-compatible expander for a SAS architecture, is configured to follow a set of discovery rules that are applied following detection of a discovery-triggering event, such as system power up or reset. According to one of the discovery rules, the expander waits until after a specified duration following the detected discovery-triggering event before passing on, to any other expanders, any requests to check the status of their discovery processing. Using appropriate values for the specified durations for different expanders, the discovery procedure will be performed without any infinite-messaging problems, even when the device architecture has a loop.

Abstract: A storage system includes a plurality hard disk drives and a plurality of solid-state drives and a storage controller operable to manage the hard disk drives and solid-state drives as a plurality of logical volumes, and categorize input/output requests to the logical volumes into types based on sizes of the input/output requests (e.g., smaller and larger). The storage controller is also operable to reconfigure the logical volumes from the hard disk drives and the solid-state drives based on the types of the input/output requests to the logical volumes. A first of the reconfigured logical volumes occupies a first portion of at least one of the solid-state drives and a first portion of at least one of the hard disk drives. The storage controller is further operable to direct the first type of the input/output requests to the first portion of the solid-state drive occupied by the first reconfigured logical volume.

Abstract: Systems and methods presented herein provide for input/output shipping between storage controllers in a storage system. One storage system comprises a plurality of logical volumes, a host driver operable to process input/output requests to the logical volumes, and a plurality of storage controllers coupled between the server and the logical volumes. A first of storage controllers is operable to receive an input/output request from the host driver for one of the logical volumes, and transfer a command to a second of the storage controllers to retrieve the data of the input/output request. The second storage controller processes the command from the first storage controller, and retrieves the data associated with the input/output request.

Abstract: A modified or host driver operable on a host computer communicates with a host interface of a PCIe adapter. A controller memory space is managed by the kernel space of the host operating system. The modified driver entirely avoids the overhead associated with making a copy from the application or user space to a separate kernel space managed by the operating system in the host computer. The modified driver uses a base address register to identify the location of the cache storage in the controller memory space. The size of the cache store is communicated to the modified driver upon a power on initialization of the PCIe adapter and the host computer. A memory map managed by the modified driver identifies cache storage locations as an offset from the base address register.

Abstract: A data storage system controller designates critical drives for staggered spin up and other, non-critical drives for spin up only when the controller notifies the appropriate expander. Each expander in the data storage system maintains configuration information for each PHY of the expander and reports completion of spin up when all of the drives designated “staggered spin up” have been spun up. Alternatively, an expander maintains PHY configuration data, designating each PHY as “staggered spin up,” “host notify” or “disabled.” At boot time, only devices connected to PHYs designated “staggered spin up” are spun up in cycles before reporting spin up completion to a host device.

Abstract: The present disclosure is directed to a method for managing a cache based on a charge of a power source. The method includes the step of determining a charge of the power source at a first time instance. The method also includes the step of designating for write back cache an amount of data in the cache which can be offloaded from the cache based on the charge of the power source at the first time instance. The method also includes the step of designating as write through cache an amount of data remaining in the cache which was not designated as write back cache.

Abstract: Systems and methods presented herein provide for backing up cached dirty data during power outages. In one embodiment, a system includes a controller operable to process input/output requests from a host system, and a cache memory operable to cache dirty data pertaining to the input/output requests. The system also includes a nonvolatile memory operable to back up the dirty data during a power outage. The controller comprises a hardware register operable to map directly to the cache memory to track the dirty data. The controller is further operable to detect the power outage, and, based on the detected power outage, to direct the hardware register to perform a direct memory access (DMA) of the dirty data in the cache memory according to the mapping between the hardware register and the cache memory, and to write the dirty data to the nonvolatile memory.

Abstract: Systems and methods herein provide a storage system that optimizes the boot time when the storage system is rebooted. One embodiment includes a storage controller operable to determine a topology of one or more storage devices. The storage controller stores the topology in memory. When the storage controller detects a system reboot event, it provides the stored topology to the host and directs the host to reboot with the stored topology.

Abstract: Methods and structure are provided for provisioning a Redundant Array of Independent Disks (RAID) volume via an expander that can be used to provision a RAID volume managed by an external RAID controller. The structure includes a Serial Attached SCSI (SAS) expander. The expander comprises physical links with transceivers (PHYs) that directly couple with storage devices, a protocol target and a control unit. The control unit provisions a first RAID volume with multiple storage devices that are directly coupled with the PHYs, and is further masks the storage devices from a SAS domain, by presenting the PHYs directly coupled with the multiple storage devices as a single PHY coupled with a single logical device. The control unit is also operable to provision a portion of a second RAID volume on the logical device in response to the expander receiving a command from a RAID controller.

Abstract: The disclosure is directed to a system and method for managing a plurality of storage devices. In an embodiment, at least one enclosure is configured to contain or support a plurality of storage devices accessible by a plurality of initiators. The enclosure further includes or is coupled to a power management controller in communication with the plurality of storage devices. The power management controller is configured to switch one or more storage devices of the plurality of storage devices from a first activity state to a second activity state when the one or more storage devices receive less than a selected number of data transfer requests over a specified time interval, where the one or more storage devices consume less power in the second activity state than in the first activity state.

Abstract: Methods and structure are provided for creating and managing unused storage capacity in Redundant Array of Independent Disks (RAID) systems. One embodiment is a RAID controller that includes a controller operable to create and manage a logical volume out of storage space that would otherwise not be used by a RAID system. The logical volume is then exposed to the host operating system as a logical volume where the storage space can be used as a cache device for a host operating system.