By pervasiveness of cloud computing, a colossal amount of applications from gigantic organizations increasingly tend to rely on cloud services. These demands caused a great number of applications in form of couple of virtual machines (VMs) requests to be executed on data centers’ servers. Some of applications are as big as not possible to be processed upon a single VM. Also, there exists several distributed applications such as MapReduce projects which exploit much number of VMs dispersed over physical machines (PMs) attached with high speed networks. These types of VMs involve mutual traffic transferring which is completely processed as an atomic application. High volume of traffic transfer among VMs may saturate network links and leads performance bottleneck for both data center and applications which seriously threat users’ service level agreement (SLA). Furthermore, communication energy consumption increases when network devices are heavily in use. This paper addresses the virtual machine placement (VMP) problem by considering inter-VM communications on VL2 topology. This is an optimization problem with the aim of network traffic transferring minimization. Dependent VMs are tried to be co-hosted or to be placed in close neighborhoods to minimize the amount of total traffic streaming over the network. A combined meta-heuristic approach based and ACO and GA algorithms is employed to solve the problem. The results of simulations imply the superiority of our proposed approach in comparison with other state-of-the-art approaches in terms of reducing total traffic flow, saving energy, and declining resource dissipation in servers. Manuscript profile

The large number of applications manages time varying data. Existing database technology seldom supports temporal database, TDB, according to time aspects. These intrinsic temporal database applications rely on such database which stores and retrieves time referenced data. Moreover, applications need to be managed on common data items access simultaneously and to be precluded from inconsistency as soon as possible which is the main task of concurrency controller or CC in short. The method used by CC in typical DB differs from its attitude with TDB. The variety algorithms were proposed regarding to TDB properties by reduction of granule size and decreasing the rate of conflicts to satisfy good performance, but none of them has achieved robust results. There are two categories of CC such as pessimistic and optimistic. In this paper new approach, with considering the TDB aspects, based on optimistic method has been suggested. It reclines the size of granule as data item appropriately and recognizes the conflicts swiftly. Consequently, we compare our proposed algorithm with pervasive 2PL-pessimistic approach. The outcome shows that new proposed algorithm has high degree of trade off with satisfying near conflict time detection and high rate of parallelism metrics. Manuscript profile