Abstract: A method, device, and system are provided for the automatically assigning identification numbers or enclosure IDs to enclosures in a data storage system. Each enclosure is assigned a unique enclosure ID that can be used to reference the enclosure in the data storage system. The enclosure IDs are generated and assigned to enclosures based on the network topology. Specifically, each enclosure is assigned an enclosure ID that not only uniquely identifies the enclosure but the enclosure ID can be used to determine the location of the enclosure in the data storage system.

Abstract: A system for performing an efficient mirrored posted-write operation having first and second RAID controllers in communication via a PCI-Express link is disclosed. The first bus bridge transmits a PCI-Express memory write request TLP to the second bus bridge. The TLP header includes an indication of whether the first CPU requests a certification that certifies the payload data has been written to the second write cache memory. If the indication requests the certification, the second bus bridge automatically transmits the certification to the first bus bridge independent of the second CPU, after writing the payload data to the second write cache memory. The first bus bridge generates an interrupt to the first CPU in response to receiving the certification. The certified transfer may be used to validate and/or invalidate mirrored copies of a write cache directory on the RAID controllers, among other uses.

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.

Abstract: A SAS expander includes SAS PHYs for transceiving signals with SAS devices on corresponding SAS links coupled to the SAS PHYs. The SAS expander includes status registers that provide fault detection parameters concerning communications on the SAS links. A microprocessor of the SAS expander identifies faulty communications on one of the SAS links, based on the fault detection parameters, and disables a corresponding one of the SAS PHYs coupled to the SAS link on which the microprocessor identified the faulty communications. The microprocessor may also report the PHY disabling to a SAS initiator. The microprocessor may also re-enable the PHY after corrective action is taken, such as in response to user input, an indication from a SAS device, or automatically detecting the corrective action. The expander may also automatically take the corrective action. The fault detection parameters may include error counters and corresponding thresholds, interrupt indicators, and state values.

Abstract: A server blade includes a printed circuit board (PCB), including a connector for connecting the blade to a backplane comprising a local bus, and a removal mechanism for use by a person to disconnect the connector from the backplane for removal of the blade from a chassis while the chassis is powered up. The server blade also includes an I/O link and a server, each affixed on the PCB. The server transmits packets on the I/O link to a storage controller enclosed in the chassis. The packets include commands to transfer data to at least one storage device controlled by the storage controller. A portion of the storage controller, affixed on the PCB, receives the packets from the server on the I/O link, and forwards the commands on the backplane local bus to another portion of the storage controller affixed on a separate PCB enclosed in the chassis.

Abstract: A method for transferring data within a network storage appliance is disclosed. The method includes transmitting a packet on an I/O link from a server to a first portion of a storage controller. Transmitting the packet on the I/O link is performed within a single blade module in a chassis enclosing the storage appliance. The method also includes forwarding a data transfer command within the packet from the first portion of the storage controller to a second portion of the storage controller. Forwarding the data transfer command is performed via a local bus on a backplane of the chassis through a connector of the blade connecting the blade to the backplane.

Abstract: A network storage appliance includes a chassis, enclosing a storage controller and first and second servers. The storage controller has first and second I/O ports for coupling to first and second I/O links. The storage controller controls a plurality of physical disk drives and presents the plurality of physical disk drives as one or more logical disk drives on the first and second I/O links. The servers each have an I/O port for coupling to a respective one of the first and second I/O links. Each of the servers transmits packets to the storage controller over the respective I/O link. The packets include block-level protocol disk commands each identifying one of the logical disk drives, such as SCSI block level protocol commands each identifying one of said logical disk drives as a SCSI logical unit. The I/O links may be FibreChannel, Ethernet, or Infiniband links, for example.

Abstract: A method, device, and system are provided for the automatically assigning identification numbers or enclosure IDs to enclosures in a data storage system. Each enclosure is assigned a unique enclosure ID that can be used to reference the enclosure in the data storage system. The enclosure IDs are generated and assigned to enclosures based on the network topology. Specifically, each enclosure is assigned an enclosure ID that not only uniquely identifies the enclosure but the enclosure ID can be used to determine the location of the enclosure in the data storage system.

Abstract: An apparatus for deterministically killing one of redundant servers integrated into a network storage appliance chassis along with at least one storage controller is disclosed. Each server can generate a kill signal on a backplane of the chassis to the other server in response to a stopped heartbeat of the other server in order to disable the I/O ports of the other server on a network so the live server can reliably take over the identity of the other server on the network. Unlike conventional kill paths, such as an Ethernet cable connecting the two servers in separate chassis, the present invention does not require the failed server to be operational since the kill path is substantially a direct reset to the I/O ports of the failed server. One server raises a shield before killing the other server to avoid both servers killing each other simultaneously.

Abstract: An apparatus is disclosed for deterministically performing active-active failover of redundant servers in response to a failure of a link on which each server provides a heartbeat to the other server. Each of the servers is configured to take over the identity of the other server on a common network in response to detecting a failure of the other server's link heartbeat. Each server provides a status indicator to a storage controller indicating whether the other server's link heartbeat stopped. The storage controller determines the link has failed if both of the status indicators indicate the other server's heartbeat stopped, and responsively kills one of the servers. The storage controller also receives a heartbeat directly from each server. If only one direct heartbeat stops when the status indicators indicate the link heartbeats stopped, then the storage controller detects one server has failed and inactivates the failed server.

Abstract: A bus bridge on a primary RAID controller receives user write data from a host and writes the data to its write cache and also broadcasts the data over a high speed link (e.g., PCI-Express) to a secondary RAID controller's bus bridge, which writes the data to its mirroring write cache. However, before writing the data, the second bus bridge automatically invalidates the cache buffers to which the data is to be written, which alleviates the primary controller's CPU from sending a message to the secondary controller's CPU to instruct it to invalidate the cache buffers. The secondary controller CPU programs its bus bridge at boot time with the base address of its mirrored write cache to enable it to detect that the cache buffer needs invalidating in response to the broadcast write, and with the base address of its directory that includes the cache buffer valid bits.

Abstract: An application server blade for an embedded storage appliance is disclosed. The blade includes a printed circuit board (PCB) with a connector for connecting to a chassis backplane including a local bus. Affixed on the PCB is a server, a portion of a storage controller, and an I/O link coupling the server and storage controller portion. The server transmits packets on the I/O link to the storage controller portion. The packets include commands to transfer data to a storage device controlled by the storage controller. The storage controller portion receives the packets from the server on the I/O link and forwards the commands on the backplane local bus to another portion of the storage controller affixed on a separate PCB also enclosed in the chassis. The blade also includes a removal mechanism for hot-replacement of the blade in the chassis. The blade architecture facilitates software reuse.

Abstract: A network storage appliance integrates a plurality of servers and a plurality of storage controllers into a single chassis. The storage controllers control transfers of data between the servers and storage devices controlled by the storage controllers. The servers and storage controllers comprise a plurality of field replaceable units (FRUs) that plug into a backplane also enclosed in the chassis. The FRUs are redundant such that any one of the FRUs may fail without incurring loss of availability of the data stored on the storage devices. One of the storage controllers detects a failure of one of the servers and responsively kills the failed server. The failure may be a stopped heartbeat from the failed server. Additionally, one of the storage controllers detects a failure of a heartbeat link coupling the servers and responsively inactivates one of the servers to enable failover to the live server.

Abstract: An apparatus and method for deterministically killing one of redundant servers on a common network is disclosed. The apparatus includes a chassis that encloses the servers and a storage controller, status indicators generated by the servers to the storage controller, and kill controls, generated by the storage controller to respective ones of the servers, each for killing a respective one of the servers. The status indicators and kill controls are wholly enclosed in the chassis. The kill controls deterministically disable the killed server on the network independently of the state of the server to be killed. That is, the server does not need to be able to respond to a command to be disabled on the network. In one embodiment, the kill controls comprise reset signals. After the storage controller deterministically kills one of the servers, the other server takes over the identity of the killed server on the network.

Abstract: A SAS expander includes SAS PHYs for transceiving signals with SAS devices on corresponding SAS links coupled to the SAS PHYs. The SAS expander includes status registers that provide fault detection parameters concerning communications on the SAS links. A microprocessor of the SAS expander identifies faulty communications on one of the SAS links, based on the fault detection parameters, and disables a corresponding one of the SAS PHYs coupled to the SAS link on which the microprocessor identified the faulty communications. The microprocessor may also report the PHY disabling to a SAS initiator. The microprocessor may also re-enable the PHY after corrective action is taken, such as in response to user input, an indication from a SAS device, or automatically detecting the corrective action. The expander may also automatically take the corrective action. The fault detection parameters may include error counters and corresponding thresholds, interrupt indicators, and state values.

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.

Abstract: A fault-tolerant RAID system is disclosed. The system includes redundant RAID controllers coupled by a PCI-Express link. When a PCI-Express controller of one of the RAID controllers receives a PCI-Express memory write request transaction layer packet (TLP), it interprets a predetermined bit in the header as an interrupt request flag, rather than as its standard function specified by the PCI-Express specification. If the flag is set, the PCI-Express controller interrupts the processor after storing the message in the payload at the specified memory location. In one embodiment, an unused upper address bit in the header is used as the interrupt request flag. Additionally, unused predetermined bits in the TLP header are used as a message tag to indicate one of a plurality of message buffers on the receiving RAID controller into which the message has been written. The PCI-Express controller sets a corresponding bit in a register to indicate which message buffer was written.

Abstract: An apparatus is disclosed for deterministically performing active-active failover of redundant servers in response to a failure of a link on which each server provides a heartbeat to the other server. Each of the servers is configured to take over the identity of the other server on a common network in response to detecting a failure of the other server's link heartbeat. Each server provides a status indicator to a storage controller indicating whether the other server's link heartbeat stopped. The storage controller determines the link has failed if both of the status indicators indicate the other server's heartbeat stopped, and responsively kills one of the servers. The storage controller also receives a heartbeat directly from each server. If only one direct heartbeat stops when the status indicators indicate the link heartbeats stopped, then the storage controller detects one server has failed and inactivates the failed server.

Abstract: A storage controller configured to adopt orphaned I/O ports is disclosed. The controller includes multiple field-replaceable units (FRUs) that plug into a backplane having local buses. At least two of the FRUs have microprocessors and memory for processing I/O requests received from host computers for accessing storage devices controlled by the controller. Other of the FRUs include I/O ports for receiving the requests from the hosts and bus bridges for bridging the I/O ports to the backplane local buses in such a manner that if one of the processing FRUs fails, the surviving processing FRU detects the failure and responsively adopts the I/O ports previously serviced by the failed FRU to service the subsequently received I/O requests on the adopted I/O ports. The I/O port FRUs also include I/O ports for transferring data with the storage devices that are also adopted by the surviving processing FRU.