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This article is devoted to verification of the bully election algorithm for distributed systems with TLA+ and PlusCal. In this work, we show an overview of the basic information about distributed systems, then we show definition of election algorithms for distributed systems, after that we provide a full description of the bully election algorithm for distributed systems. Later in this article, we show the model of the distributed algorithm created with TLA+ and PlusCal. Then we describe the main parts of this model. Next, we illustrate results of verification of this model. The verification was done using TLC ‒ a model checker and simulator for executable TLA+ specifications. As a result of the verification, it was possible to establish that the declared properties of safety and liveness are fully satisfied for all possible states of the system.

Distributed database servers are very popular as they provide data availability, reliability, replication, and partition for both homogeneous as well as heterogeneous software and hardware. In this paper, we analyze the previous works on load balancing of database servers. Further we also propose an algorithm for controlling job distribution at the database servers in different node partitions. We also formulate a methodology for load status evaluation of database servers to balance their loads for effective load status management. The load status of the database servers depends on three important parameters namely processor, RAM, and bandwidth. On the basis of load status, the clients'/users' requests can then be directed to another database in a distributed environment in order to balance the load effectively to meet user demands in an unobtrusive manner. [ABSTRACT FROM AUTHOR]

In distributed computing systems, if an elected leader node fails, the other nodes of the system need to elect another leader. The bully algorithm is a classical approach for electing a leader in a synchronous distributed computing system. This paper presents an enhancement of the bully algorithm, requiring less time complexity and minimum message passing. This significant gain has been achieved by introducing node sets and tie breaker time. The latter provides a possible solution to simultaneous elections initiated by different nodes. In comparison with the classical algorithm and its existing modifications, this proposal generates minimum messages, stops redundant elections, and maintains fault-tolerant behaviour of the system.