Example implementations relate to consensus protocols in a stretched network. According to an example, a distributed system includes continuously monitoring network performance and/or network latency among a cluster of a plurality of nodes in a distributed computer system. Leadership priority for each node is set based at least in part on the monitored network performance or network latency. Each node has a vote weight based at least in part on the leadership priority of the node. Each node's vote is biased by the node's vote weight. The node having a number of biased votes higher than a maximum possible number of votes biased by respective vote weights received by any other node in the cluster is selected as a leader node.

A system and a method are disclosed that provides a data replication management technique for a distributed environment that eliminates a need to order members of a replica set. A node of a node cluster in the distributed system may be configured to send in parallel an IO request to each respective member of the replica set. Reponses are received from members of the replica set that indicate a completion status of the IO request at the replica set member sending the IO response. A request is sent to other nodes of the node cluster to remove a replica from the replica set based on an error response received from the replica. The replica that responded with the error response is removed from the replica set based on an agreement of nodes of the node cluster to remove the replica from the replica set.

A redundant processing system with profile-based monitoring is disclosed. In embodiments, the redundant system includes two or more redundant lanes, each lane having equivalent processing components. In a testing state, template processors and hardware monitoring sensors are connected to a selected trusted lane and input vectors submitted thereto; the hardware sensors characterize the response of the selected lane and the resulting testing data compiled into system templates. In an operational environment, the template processors send challenges based on the input vectors to each of the redundant lanes in real time, collecting response data from each lane via identical sets of monitoring sensors. The template processors correlate the response data with the corresponding system templates, identifying anomalous lanes and system anomalies based on discorrelations between the response data and the system templates.

A processing system encompasses several processing devices and a comparison device. A method for controlling the processing system encompasses: processing of identical information items by the processing devices using associated processing processes; furnishing a characteristic value of each processing process, respectively as a function of the processing that has occurred; and comparing the characteristic values by way of the comparison device and determining a defectively operating processing process on the basis of the comparison. The defectively operating processing process is replaced by a processing process restarted on the same processing device.

A method and system for performing a flexible Byzantine fault tolerant (BFT) protocol. The method includes sending, from a client device, a proposed value to a plurality of replica devices and receiving, from at least one of the plurality of replica devices, a safe vote on the proposed value. The replica device sends the safe vote, based on a first quorum being reached, to the client device and each of the other replica devices of the plurality of replica devices. The method further includes determining that a number of received safe votes for the proposed value meets or exceeds a second quorum threshold, selecting the proposed value based on the determination, and setting a period of time within which to receive additional votes. The method further includes, based on the period of time elapsing without receiving the additional votes, committing the selected value for the single view.

Systems, methods, and computer-readable storage media for receiving, at a central server from a first remote data transmission device, first product data for a product at a first location and second product data for the product from a second remote data transmission device at a second location. The respective data is processed sequentially, then determined to contain identical data, such that the system selects a data transmission device as the leader. Then, at a second time, the system receives receiving additional product data from only the selected data transmission device and not from the ignored transmission device, then processes the additional product data as though it had been received from both the first remote data transmission device and the second remote data transmission device.

A method, an apparatus, and a computer-readable storage medium having instructions for cancelling a redundancy of two or more redundant modules. Results of the two or more redundant modules are received; reliabilities of the results are ascertained; and, based on the ascertained reliabilities, an overall result is determined from the results. The overall result is output for further processing.

An abnormality is diagnosed in a control system including a plurality of controllers adopting a redundant configuration, a diagnosing apparatus that diagnoses a control system. The control system includes a plurality of controllers adopting a redundant configuration; and an interface apparatus that outputs control output data, which is based on a plurality of redundant pieces of control data received from the plurality of controllers, to a device under control. The diagnosing apparatus includes a statistical information acquiring section that acquires statistical information including adoption/non-adoption of the control data from each of the plurality of controllers in the interface apparatus; and a diagnosing section that diagnoses the control system based on the statistical information.

The voter circuit and method determines a voted output among plural inputs each carrying circular data. To supply the voted output, a statistical average (e.g., mean or median) is computed by grouping the plural inputs into pairs, and for each pair generating a minimum angular difference by selecting the minimum of (a) the absolute difference between the pairs of inputs, and (b) the conjugate of the absolute difference between the pairs of inputs. The voted output is a statistical average generated from the minimum angular difference.

A method includes identifying multiple apportionments, where each apportionment identifies numbers of bit copies to be stored in at least one memory for at least some bits of a data value. The method also includes, for each apportionment, estimating a numerical error associated with use of the apportionment with a specified function, where the numerical error is estimated by creating errors in bit copies of multiple data values processed using the specified function. The method further includes combining portions of different ones of the apportionments having lower estimated numerical errors to create multiple derived apportionments. The method also includes, for each derived apportionment, estimating a numerical error associated with use of the derived apportionment with the specified function. In addition, the method includes selecting a final apportionment for use with the specified function, where the final apportionment includes or is based on at least one of the derived apportionments.