Preface

The e-mail service is increasingly important for organizations and their employees. As such, it requires constant monitoring to solve any performance issues and to maintain an adequate level of service. To cope with the increase of traffic as well as the dimension of organizations, several architectures have been evolving, such as cluster or cloud computing, promising new paradigms of service delivery, which can possibility solve many current problems such as scalability, increased storage and processing capacity, greater rationalization of resources, cost reduction, and increase in performance. However, it is necessary to check whether they are suitable to receive e-mail servers, and as such the purpose of this dissertation will concentrate on evaluating the performance of e-mail servers, in different hosting architectures. Beyond computing platforms, was also analze different server applications. They will be tested to determine which combinations of computer platforms and applications obtained better performances for the SMTP, POP3 and IMAP services. The tests are performed by measuring the number of sessions per ammount of time, in several test scenarios. This dissertation should be of interest for all system administrators of public and private organizations that are considering implementing enterprise wide e-mail services.