Abstract: A latching device for latching a storage device module into a storage chassis is provided. The latching device includes a latch member having a latching end and a spring end opposite the latching end, the latch member slidingly disposed within a front bezel of the storage device module and being movable between a latching position and a releasing position. The latching device also includes a latch spring between a bearing surface of the front bezel and the spring end of the latch member. The latch spring is in increased compression when the latch member transitions from the latching position to the releasing position, and the latch spring is in decreased compression when the latch member transitions from the releasing position to the latching position. The latching end extends through a latch hole in a side member of the storage chassis for locking the storage device module in the chassis.

Abstract: A spring for ejecting a storage device module from a chassis is provided. The spring includes a first end, where the first end is held captive when the spring is installed in the chassis. The spring includes a second end, opposite the first end, and a body between the first and second ends. The body is formed with serpentine bends proceeding linearly between the first and second ends and in a common plane with the first end. The second end is oriented orthogonal to the common plane. The spring is in expansion when the storage device module is inserted into the chassis. The storage device module pushes against the second end when the storage device module is fully inserted into the chassis. The spring exerts force outward from the chassis when expanded.

Abstract: A method for maintaining reliable communication on a bidirectional communication link is provided. A receiver on the bidirectional communication link detects an error and maintains a count of detected errors. The transmitter on the bidirectional communication link polls the receiver in order to determine the count of detected errors, and performs a downshift evaluation for the bidirectional communication link. In response to performing the downshift evaluation for the bidirectional communication link, the transmitter maintains a transmission speed of the bidirectional communication link if the downshift evaluation determines that forgoing transmission speed downshift is required for the bidirectional communication link, and reduces the transmission speed of the path if the downshift evaluation determines that transmission speed downshift is required for the bidirectional communication link.

Abstract: A method for maintaining reliable communication on a link between an expander and a storage device is provided. The method includes detecting, by a processor coupled to the link, an error corresponding to the link, and maintaining a count of detected errors for the link, by the processor. The method also includes determining, by the processor, if the count of detected errors is above a first error threshold. If the count of detected errors is not above the first error threshold, then the method repeats the detecting, maintaining, and determining steps. If the count of detected errors is above the first error threshold, then the method provides the processor placing the storage device into a segregated zone.

Abstract: A RAID controller is disclosed. The controller controls at least one redundant array of physical disks, receives I/O requests for the array from host computers, and responsively generates disk commands for each of the disks. Some commands specify host computer user data, and others specify internally generated redundancy data. The controller executes coalescer code that maintains the commands on a queue for each disk. Whenever a disk completes a command, the coalescer determines whether there are two or more commands on the disk's queue that have the same read/write type and specify adjacent locations on the disk, and if so, coalesces them into a single command, and issues the coalesced command to the disk. The coalescer immediately issues a received command, rather than queuing it, if the number of pending commands to the disk is less than a maximum command depth, which may be different for each disk.

Abstract: A method for a storage controller to rebalance storage components within a storage tier is provided. The method maintains a linked list for each component, and each component includes a plurality of pages. Each linked list is ordered according to hot and cold pages and includes an identifier for each page. The method calculates a percent range of hot and cold pages for each component, and identifies a fullest and least full component. The method compares a random percent to the hot and cold percent ranges for the fullest component. If the random percent falls within the hot range, the method moves a selected hot page from the fullest component to an empty page in the least full component. If the random percent falls within the cold range, the method moves a selected cold page from the fullest component to an empty page in the least full component.

Abstract: A system, device, and method are provided for managing one or more computer resource systems. More specifically, the present invention provides for the automated maintenance of a computer resource and gradual change of management policies based upon a state of the computer resource. Moreover, the present invention is capable of generating commands related to changing the configuration of the computer resource and maintaining a log of generated commands for later reference by a system administrator. Further, the present invention includes one or more human user written policies, in some computer understandable format, to manage the system and accomplish specific goals based on the system's dynamic nature or behavior.

Abstract: A method for maximizing I/O requests to a target port is provided. The method includes a storage controller obtaining an initiator allowed queue depth, receiving an I/O request and a current sequence identifier from an initiator logged into the target port, and determining if the initiator allowed queue depth is equal to a first queue depth corresponding to the initiator. If the initiator allowed queue depth is equal to the first queue depth then returning a queue full indication and a maximum sequence identifier equal to the current sequence identifier to the initiator. If the initiator allowed queue depth is not equal to the first queue depth then placing the I/O request on a queue, incrementing the first queue depth, and adjusting the maximum sequence identifier. Adjusting the maximum sequence identifier includes adding the current sequence identifier to the initiator allowed queue depth and subtracting the first queue depth.

Abstract: A method, device, and system for resetting snapshots are provided. The reset of a snapshot incorporates the traditional snapshot delete and snapshot create operations into a single operation. Additionally, a snapshot created under the reset operation may receive an array partition from a snapshot being deleted under the same snapshot reset operation thereby retaining its identifying characteristics.

Abstract: A method, device, and system for resetting snapshots are provided. The reset of a snapshot incorporates the traditional snapshot delete and snapshot create operations into a single operation. Additionally, a snapshot created under the reset operation may receive an array partition from a snapshot being deleted under the same snapshot reset operation thereby retaining its identifying characteristics.

Abstract: A network storage appliance is disclosed. The appliance includes a chassis enclosing a backplane, and a server enclosed in the chassis and coupled to the backplane. The appliance also includes storage controllers enclosed in the chassis, each coupled to the backplane, which control transfer of data between the server and storage devices coupled to the storage controllers. The storage controllers also control transfer of data between the storage devices and computers networked to the appliance and external to the appliance. The storage controllers and the server comprise a plurality of hot-replaceable blades. Any one of the plurality of blades may be replaced during operation of the appliance without loss of access to the storage devices by the computers. In one embodiment, the server executes storage application software, such as backup software for backing up data on the storage devices, such as to a tape device networked to the server.

Abstract: A data storage system with a controller that receives shock data from a shock detection sensor and methods utilizing such a controller are provided. The data storage system controller receives information or signals regarding shock events from a shock sensor, enabling the data storage system controller to take remedial action. The particular remedial action taken may be dependent on the severity of the detected shock event. The data storage system controller may receive information regarding shock events from shock sensors provided separately from the data storage system controller, allowing the data storage system controller to take remedial action that is tailored to the locale of a shock event.

Abstract: A data storage system controller having a shock detection sensor and methods utilizing such a controller are provided. The data storage system controller receives information or signals regarding shock events from the associated shock sensor, enabling the data storage system controller to take remedial action. The particular remedial action taken may be dependent on the severity of the detected shock event. The data storage system controller may also receive information regarding shock events from shock sensors provided separately from the data storage system controller, allowing the data storage system controller to take remedial action that is tailored to the locale of a shock event.

Abstract: A method for maximizing I/O requests to a target port is provided. The method includes a storage controller obtaining an initiator allowed queue depth, receiving an I/O request and a current sequence identifier from an initiator logged into the target port, and determining if the initiator allowed queue depth is equal to a first queue depth corresponding to the initiator. If the initiator allowed queue depth is equal to the first queue depth then returning a queue full indication and a maximum sequence identifier equal to the current sequence identifier to the initiator. If the initiator allowed queue depth is not equal to the first queue depth then placing the I/O request on a queue, incrementing the first queue depth, and adjusting the maximum sequence identifier. Adjusting the maximum sequence identifier includes adding the current sequence identifier to the initiator allowed queue depth and subtracting the first queue depth.

Abstract: A storage system includes two RAID controllers, each having two SAS initiators coupled to a zoning SAS expander. The expanders are linked by an inter-controller link and create a SAS ZPSDS. The expanders have PHY-to-zone mappings and zone permissions to create two distinct SAS domains such that one initiator of each RAID controller is in one domain and the other initiator is in the other domain. The disk drives are dual-ported, and each port of each drive is in a different domain. Each initiator can access every drive in the system, half directly through the local expander and half indirectly through the other RAID controller's expander via the inter-controller link. Thus, a RAID controller can continue to access a drive via the remote path in the remote domain if the drive becomes inaccessible via the local path in the local domain.

Abstract: A method for a storage controller to rebalance storage components within a storage tier is provided. The method maintains a linked list for each component, and each component includes a plurality of pages. Each linked list is ordered according to hot and cold pages and includes an identifier for each page. The method calculates a percent range of hot and cold pages for each component, and identifies a fullest and least full component. The method compares a random percent to the hot and cold percent ranges for the fullest component. If the random percent falls within the hot range, the method moves a selected hot page from the fullest component to an empty page in the least full component. If the random percent falls within the cold range, the method moves a selected cold page from the fullest component to an empty page in the least full component.

Abstract: A method for a storage controller to write a data block to one of a plurality of storage components is provided. The storage controller receives a write request from a host computer, and determines at least a portion of the data block includes a Logical Block Address (LBA) that is not currently mapped to a physical page of storage. The storage controller calculates availability for each storage component within the plurality of storage components, and selects the storage component with a highest calculated availability from the plurality of storage components. The storage controller next determines a next available physical page within the selected storage component. Finally, the storage controller writes the at least a portion of the data block including LBAs that are not currently mapped to a physical page of storage to the next available physical page.

Abstract: A method for providing reduced power consumption in a computer memory system is provided. The method includes calibrating, by a processor, a volatile memory of the computer memory system at a first and a second operating speed, where the second operating speed is higher than the first operating speed. The method also includes operating, by a memory controller coupled to the processor and the volatile memory, the volatile memory at the second operating speed if a main power source provides power to the computer memory system. The method further includes operating, by the memory controller, the volatile memory at the first operating speed if a backup power source provides power to the memory controller and the volatile memory. The backup power source provides power to the memory controller and the volatile memory when there is a loss of main power to the computer memory system.

Abstract: A method for providing reduced power consumption in a computer memory system is provided. The method includes transferring, by a memory controller coupled to a volatile memory, a non-volatile memory, and a buffer, first data from the volatile memory to the buffer. The buffer stores less data than the volatile memory and the non-volatile memory. The method also includes placing the volatile memory into self-refresh mode after transferring the first data to the buffer. The method further includes conveying the first data from the buffer to the non-volatile memory, where the amount of first data exceeds a predetermined threshold. While conveying the first data, the memory controller takes the volatile memory out of self-refresh mode when the amount of first data in the buffer reaches the predetermined threshold. The volatile memory is ready to transfer second data to the buffer when the memory controller is finished transferring the first data.

Abstract: A method, device, and system are provided for determining when to re-initialize a backing store in a data storage system. More specifically, when all snapshots associated with a specified backing store are either being deleted or are marked for deletion the backing store is re-initialized rather than deleting each snapshot independently. The re-initialization of the backing store provides for a quicker way to delete all snapshots than can be achieved by deleting each snapshot independently.