Need for speed? On quality of experience for file storage services

Cloud computing is receiving growing attention by researchers from a variety of disciplines. However, so far only a few studies exist that investigate the Quality of Experience (QoE) of cloud services, including the category of personal file storage services like Dropbox or Livedrive, from an end user perspective. The contribution of this paper is a methodology and the results of four different user studies towards a situational QoE model for file storage services. In order to obtain insights in existing usage practices and to detect possible QoE influencing factors and relevant features, we conducted an online survey amongst users of personal cloud storage services in general (N=349) and one specifically targeted at users of one of the major popular cloud storage services, namely Dropbox (N=49). A third study (N=13) on mobile Dropbox further investigated QoE and specific use cases in a mobile context, via smartphones and tablets. Based on these results, typical usage situations as well as short-term and long-term QoE influence factors were derived which included user profile, context and situation, as well as system level influences. In a fourth lab study (N= 52) the impact of waiting times, i.e. short-term QoE influences on system level during the regular usage of Dropbox, is investigated for different situations and use cases are obtained from the first three studies. As an outcome of our studies, we formulate research questions driving the agenda towards measuring and modeling QoE for cloud-based file storage services