Avago Technologies General IP (Singapore) Pte. Ltd.

Lsi Corporation

Naresh Madhusudana

Naveen Krishnamurthy

Sridhar Rao Veerla

Raghavendra Channagiri Nagendra

Giridhar Danayakanakeri

Prashant Prakash Yendigiri

Kashyap Dushyantbhai Desai

Kiran Math

Darshana Lingadahalli Chandrashekarappa

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.

Cache coherency and synchronization support in expanders in a raid topology with multiple initiators

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.

Coordination techniques for redundant array of independent disks storage controllers

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.

Logical volume migration in single server high availability environments

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.

Optimizing boot time of a storage system

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.

Input/output request shipping in a storage system with multiple storage controllers

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.

Methods and structure for serial attached SCSI expanders that self-configure by setting routing attributes of their ports based on SMP requests

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.

Performance improvements in input/output operations between a host system and an adapter-coupled cache

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.

Expander for loop architectures

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.

Methods and structure establishing nested Redundant Array of Independent Disks volumes with an expander

A SAS expander includes DMD timers for each PHY so that the expander can track disconnected devices directly connected to the expander and signal a SAS controller when the DMD is exceeded. A system including such SAS expanders may reduce the load on the system controller. A controller may recognize expanders capable of tracking DMDs for backwards compatibility.

Localized device missing delay timers in SAS/SATA topology

Methods and structure are provided for performing a rebuild using a Serial Attached SCSI (SAS) expander. The SAS expander includes an SMP target operable to receive, from a Redundant Array of Independent Disks (RAID) controller, a Serial Management Protocol (SMP) command for initiating a rebuild of a RAID volume at the SAS expander. The SAS expander also includes a control unit operable to initiate a rebuild of the RAID volume based on the received SMP command from the controller, and a Serial SCSI Protocol (SSP) initiator operable to generate SSP commands for performing the RAID rebuild based upon input from the control unit.

Growing community of inventors

Bengaluru, India

Naresh Madhusudana