M.A. Torkamani - Shahid Beheshti university, Tehran, Iran
M Yaghoobi - Shahid Beheshti university, Tehran, Iran
S Bashavard - Shahid Beheshti university, Tehran, Iran

The architecture of a software system has very significant role in its success. The architecture of software considers both its functional and none-functional requirements that are called quality attributes, too. One of the main qualities attributes that is very important to the stockholders of most of the information systems and is usually selected as the architectural driver is the availability. In this article we describe the method of approaching to the high availability by using the patterns and tactics of architecture. Indeed we show by accurate calculations that if the architect choose the proper patterns and tactics of the architecture, theoretically, he/she can reach to the availability of about 99%.

Software architecture, availability, quality attribute scenario, The Architectural patterns, The Architectural tactics