Abstract: Embodiments are directed to processing read-only operations without storing the operations persistently, determining a processing order for read-only requests, and to directing read-only requests to nodes best able to handle the requests. In an embodiment, a quorum leader receives various read-only requests. The quorum leader controls process ordering for replicas in the leader's quorum. The quorum leader determines an appropriate order for processing the read-only operations, without clock-based synchronization. The quorum leader sends the read-only request to an appropriate replica in the quorum and executes the read-only request at the appropriate replica without storing the operation persistently.

Abstract: Embodiments are directed to processing read-only operations without storing the operations persistently, determining a processing order for read-only requests, and to directing read-only requests to nodes best able to handle the requests. In an embodiment, a quorum leader receives various read-only requests. The quorum leader controls process ordering for replicas in the leader's quorum. The quorum leader determines an appropriate order for processing the read-only operations, without clock-based synchronization. The quorum leader sends the read-only request to an appropriate replica in the quorum and executes the read-only request at the appropriate replica without storing the operation persistently.

Abstract: Embodiments are directed to processing read-only operations without storing the operations persistently, determining a processing order for read-only requests, and to directing read-only requests to nodes best able to handle the requests. In an embodiment, a quorum leader receives various read-only requests. The quorum leader controls process ordering for replicas in the leader's quorum. The quorum leader determines an appropriate order for processing the read-only operations, without clock-based synchronization. The quorum leader sends the read-only request to an appropriate replica in the quorum and executes the read-only request at the appropriate replica without storing the operation persistently.

Abstract: Embodiments are directed to processing read-only operations without storing the operations persistently, determining a processing order for read-only requests, and to directing read-only requests to nodes best able to handle the requests. In an embodiment, a quorum leader receives various read-only requests. The quorum leader controls process ordering for replicas in the leader's quorum. The quorum leader determines an appropriate order for processing the read-only operations, without clock-based synchronization. The quorum leader sends the read-only request to an appropriate replica in the quorum and executes the read-only request at the appropriate replica without storing the operation persistently.

Abstract: A system and method for detecting path failure in a network are described. The system and method include a network interface which receives packets over particular connections, and an agent able to monitor the network interface and start a no-traffic timer for each particular connection when a packet is received on the connection. The agent is further able, when the no-traffic timer expires, to check for outgoing data on the particular connection, and compare a count of previously sent test packets against a limit. If the count is below the limit the agent sends a new test packet on the particular connection, the test packet provides an indication of the state of a network path associated with the particular connection. If the count is above the limit the agent initiates failover procedures for the associated path.

Abstract: An efficient technique for performing remote asynchronous mirroring includes receiving a stream of command requests, performing the requested commands, relaying the requested commands to a target while embedding an explicitly-defined or implied task precedence graph in the relayed commands to enable increased concurrency in tasks performed by the target.

Abstract: A system and method for detecting path failure in a network are described. The system and method include a network interface which receives packets over particular connections, and an agent able to monitor the network interface and start a no-traffic timer for each particular connection when a packet is received on the connection. The agent is further able, when the no-traffic timer expires, to check for outgoing data on the particular connection, and compare a count of previously sent test packets against a limit. If the count is below the limit the agent sends a new test packet on the particular connection, the test packet provides an indication of the state of a network path associated with the particular connection. If the count is above the limit the agent initiates failover procedures for the associated path.

Abstract: There is disclosed a data communications link adapter providing flow of data control and status information between an input/output (I/O) Backplane and a fiber optic Frontplane. The adapter represents a melding of I/O channel extender technology and data communications technology: a dedicated processor handles link layer protocol, leaving to software only higher protocol layers; a flow-through architecture is provided by the adapter; a combination of windowing and handshaking are used; and a relatively short frame of sixteen bytes is employed. The adapter includes a backplane adapter portion which serves to interconnect host equipment, a processor portion dedicated to layer 3 (circuit operations), a protocol controller dedicated to layer 2 (physical layer) operations, a fiber optic interface portion dedicated to layer 1 (physical link) operations, and an arbiter portion which couples the processor to a data path connecting the backplane adapter and the protocol controller.