Abstract: A RAID system includes a non-volatile memory storing a first program and first and second copies of a second program, and a processor executing the first program. The first program detects the first copy of the second program is failed and repairs the failed first copy in the non-volatile memory using the second copy. The failures may be detected at boot time or during normal operation of the controller. In one embodiment, the failure is detected via a CRC check. In one embodiment, the controller repairs the failed copy by copying the good copy to the location of the failed copy. In one embodiment, the system includes multiple controllers, each having its own processor and non-volatile memory and program that detects and repairs failed program copies. The programs include a loader, an application, FPGA code, CPLD code, and a program for execution by a power supply microcontroller.

Abstract: Methods and systems for automatically and dynamically identifying capabilities of devices connected to a storage system controller port and setting operating parameters of that port are described. In particular, a storage system controller administers scanning and probing functions to determine capabilities of devices connected to a given port. Based on the determined capabilities of all or a subset of the devices connected to that port, an operating parameter is assigned to that port.

Abstract: A redundant storage controller system that robustly provides failure analysis information (FAI) to an operator of the system is disclosed. The system includes first and second storage controllers in communication with one another, such as via a PCI-Express link. When one of the controllers fails, the FAI is transferred from the failed controller to the surviving controller over the link. The operator issues a command to the surviving storage controller, which responsively provides the FAI. In one embodiment, the failed storage controller writes the FAI to the second storage controller. In one embodiment, each storage controller periodically writes the FAI before there is a failure. In one embodiment, the second storage controller reads the FAI from the failed storage controller. The FAI may include boot logs, crash logs, debug logs, and event logs. The FAI may also be written to a disk drive connected to the controllers.

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 network storage appliance is disclosed. The storage appliance includes a port combiner that provides data communication between at least first, second, and third I/O ports; a storage controller that controls storage devices and includes the first I/O port; a server having the second I/O port; and an I/O connector for networking the third I/O port to the port combiner. A single chassis encloses the port combiner, storage controller, and server, and the I/O connector is affixed on the storage appliance. The third I/O port is external to the chassis and is not enclosed therein. In various embodiments, the port combiner comprises a FiberChannel hub comprising a series of loop resiliency circuits, or a FiberChannel, Ethernet, or Infiniband switch. In one embodiment, the port combiner, I/O ports, and server are all comprised in a single blade module for plugging into a backplane of the chassis.

Abstract: A SAS expander adaptively configures a Serial-Attached-SCSI (SAS) PHY to accommodate varying lengths of a cable coupling the PHY to a remote PHY. The expander (a) configures the SAS PHY with settings of an entry of a table of PHY configuration settings, each entry in the table having different PHY configuration setting values; (b) clears a counter; (c) operates the PHY to communicate with the remote PHY for a monitoring period, after configuring the PHY and clearing the counter; (d) increments the counter when the PHY detects a PHY event during the monitoring period, and otherwise decrements the counter; (e) repeats steps (c) and (d) unless the counter rises above a threshold; and (f) when the counter rises above the threshold, repeats steps (a) through (e), wherein step (a) is performed with the settings of a different entry of the table.

Abstract: A network storage appliance is disclosed. The storage appliance includes a port combiner that provides data communication between at least first, second, and third I/O ports; a storage controller that controls storage devices and includes the first I/O port; a server having the second I/O port; and an I/O connector for networking the third I/O port to the port combiner. A single chassis encloses the port combiner, storage controller, and server, and the I/O connector is affixed on the storage appliance. The third I/O port is external to the chassis and is not enclosed therein. In various embodiments, the port combiner comprises a FibreChannel hub comprising a series of loop resiliency circuits, or a FibreChannel, Ethernet, or Infiniband switch. In one embodiment, the port combiner, I/O ports, and server are all comprised in a single blade module for plugging into a backplane of the chassis.

Abstract: A storage controller has a capacitor pack for storing energy to supply power during a main power loss, a temperature sensor that senses the capacitor pack temperature, and a CPU, which detects that the temperature of the capacitor pack has risen above a predetermined threshold while operating at a first voltage value and determines whether a projected lifetime of the capacitor pack is less than the warranted lifetime. If the projected lifetime is less than the warranted lifetime, the CPU reduces the operating voltage of the capacitor pack to a second value, in order to increase the capacitor pack lifetime. In one embodiment, the CPU reduces the voltage if an accumulated normalized running time of the capacitor pack is greater than an accumulated calendar running time. In another embodiment, the CPU reduces the voltage if a percentage capacitance drop of the capacitor pack is greater than a calendar percentage capacitance drop.

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, device, and method are provided for replicating data between different data storage systems or appliances. More specifically, the present invention affords communications between heterogeneous data storage systems that potential employ different communication protocols. A bridging communication protocol is utilized by one or both storage systems in order to accommodate different communication protocols. Alternatively, a storage appliance connecting the data storage systems may employ the bridging communication protocol.

Abstract: A method and device for cloning snapshots is provided. A new snapshot can be created by cloning an existing snapshot. The clone snapshot may use the preserved data of the existing snapshot, thereby obviating the need to copy the preserved data. Additionally, the clone snapshot may be created with a data structure for storing write data. Since the clone snapshot initially has no write data to store, the creation of the entire clone snapshot can be accomplished without copying any preserved data or write data from the existing snapshot, thereby increasing the efficiency with which a clone snapshot can be created.

Abstract: An apparatus for deterministically performing active-active failover of redundant server blades hot-pluggable into a backplane of a network storage appliance chassis is disclosed. Each server monitors the other's heartbeat on a respective path in the backplane. Other paths between the two servers on the backplane enable one server to reliably kill the other server and take over its identity on the network in response to detecting a stopped heartbeat of the other server. The apparatus is superior to a conventional heartbeat link between servers in separate chassis, such as an Ethernet cable, because it is not prone to user removal or damage since the backplane cannot be removed by a user while the appliance is operational and enables each server to know a true heartbeat failure has occurred, as opposed to failure of a conventional external heartbeat link causing each server to each think the other has failed.

Abstract: A system and method for optimizing accesses to storage devices based on RAID I/O request characteristics is disclosed. A current I/O request processed by a storage controller is analyzed for relative locality to a previous I/O request, and adjusted over time such that storage device accesses will be efficiently conducted with respect to sequential or random workloads. A storage device access profile is maintained for each storage device based on sequential or random locality characteristics of previous RAID I/O requests. The chunk locations of the two most recent accesses are sampled according to predetermined criteria in order to create a storage device access profile, which governs queue depth and I/O size parameters used to communicate with storage devices. By managing I/O requests to storage devices using this invention, performance of such a storage controller will be optimized for changing random and sequential workloads.

Abstract: A RAID controller uses a method to identify a storage device of a redundant array of storage devices that is returning corrupt data to the RAID controller. The method includes reading data from a location of each storage device in the redundant array a first time, and detecting that at least one storage device returned corrupt data. In response to detecting corrupt data, steps are performed for each storage device in the redundant array. The steps include reading data from the location of the storage device a second time without writing to the location in between the first and second reads, comparing the data read the first and second times, and identifying the storage device as a failing storage device if the compared data has a miscompare. Finally, the method includes updating the location of each storage device to a new location and repeating the steps for the new location.

Abstract: The present invention is directed to a data storage system utilizing a number of data storage devices. The data storage system features one or more storage device sleds, which may each carry multiple storage devices. Each storage device sled and its interconnected storage devices may comprise a field replaceable unit. In response to the detection of a failure associated with a field replaceable unit, information related to that failure may be stored in memory or storage associated with the field replaceable unit. Repair personnel may access the stored information in order to positively identify the failed component of the field replaceable unit in connection with the repair or replacement of that component, in order to return the field replaceable unit to service.

Abstract: A network storage appliance including one or more integrated switching devices is disclosed. The appliance includes redundant storage controllers that transfer frames of data between storage devices and host computers. The integrated switching devices include a plurality of I/O ports and a data transfer path between each of the I/O ports for providing simultaneous data transfers between multiple pairs thereof. The switches enable the appliance to simultaneously transfer frames between its I/O ports and storage device I/O ports and/or host I/O ports, thereby providing increased data transfer bandwidth over arbitrated loop configurations. Additionally, the switches are intelligent and may be programmed to achieve improved fault isolation. The appliance may also include servers that include I/O ports coupled to the switches for simultaneously transferring data with the storage controllers and/or I/O ports of devices external to the appliance.

Abstract: A method for adopting an orphaned I/O port of a storage controller is disclosed. The storage controller has first and second redundant field-replaceable units (FRU) for processing I/O requests and a third FRU having at least one I/O port for receiving the I/O requests from host computers coupled to it. Initially the first FRU processes the I/O requests received by the I/O port and the third FRU routes to the first FRU interrupt requests generated by the I/O port in response to receiving the I/O requests. Subsequently, the second FRU determines that the first FRU has failed and is no longer processing I/O requests received by the I/O port, and configures the third FRU to route the interrupt requests from the I/O port to the second FRU rather than the first FRU, in response to the determining that the first FRU has failed.

Abstract: A fault-tolerant mass storage system includes two RAID controllers that communicate via a PCI-Express link. Each controller has a bus bridge coupled to the link, a cache memory that caches user data for storage on disk drives controlled by the controllers, and a CPU. The CPU fetches and executes program instructions from a CPU memory coupled to it. The CPU programs the bus bridge with window information defining a window of locations within the CPU memory, which is less than an entirety of the CPU memory. The bus bridge receives data on the link from the other controller and if the header of a packet containing the data indicates it is destined for the CPU memory, the bus bridge translates the address of the data so as to write the data safely to the CPU memory, but only within the window and nowhere else within the CPU memory.

Abstract: A write-caching RAID controller is disclosed. The controller includes a CPU that manages transfers of posted-write data from host computers to a volatile memory and transfers of the posted-write data from the volatile memory to storage devices when a main power source is supplying power to the RAID controller. A memory controller flushes the posted-write data from the volatile memory to the non-volatile memory when main power fails, during which time capacitors provide power to the memory controller, volatile memory, and non-volatile memory, but not to the CPU, in order to reduce the energy storage requirements of the capacitors. During main power provision, the CPU programs the memory controller with information needed to perform the flush operation, such as the location and size of the posted-write data in the volatile memory and various flush operation characteristics.

Abstract: An active-active RAID system includes first and second active-active RAID controllers which efficiently share access to SATA drives. SAS expanders connect the RAID controllers to the drives. The controllers establish an affiliation within the SAS expanders with respectively-owned first and second subsets of the SATA drives. The controllers directly transmit to the SAS expanders commands destined for affiliated drives, but forward to the other RAID controller, via an inter-controller communications link, commands destined for unaffiliated drives for transmission by the other RAID controller. The controllers handle drive ownership changes by clearing previously-established affiliations, updating ownership data stored on the drives, including forwarding the update commands as necessary, and re-establishing affiliations based on the new ownership.