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 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 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 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: The verification of fault-tolerant connections between redundant controller pairs and nodes is provided. In particular, a node identifier seen at one port of the controllers is compared to the node identifier seen at another port of the controllers. In response to determining that proper connections have not been made, an error or warning signal may be generated. In addition, where supported by dynamic port configuration, the ports of the controllers may be reconfigured in response to the comparison to effect proper connections. In response to determining that proper connections have been made, a signal verifying that proper connections have been made may be generated.

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 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.