Deadline guaranteed service for multi-tenant cloud storage

It is imperative for cloud storage systems to be able to provide deadline guaranteed services according to service level agreements (SLAs) for online services. However, there are no previous works that provide the deadline guarantee specifically for cloud storage systems. In this paper, we introduce a new form of SLAs, which enables each tenant to specify a percentage of its requests it wishes to serve within a specified deadline. We first identify the multiple objectives (i.e., traffic and latency minimization, resource utilization maximization) in developing schemes to satisfy the SLAs. To satisfy the SLAs while achieving the multi-objectives, we propose a Parallel Deadline Guaranteed (PDG) scheme, which schedules data reallocation (through load re-assignment and data replication) using a tree-based bottom-up parallel process. We also enhance PDG through a prioritized data reallocation algorithm, which enables highly overloaded servers to autonomously probe nearby servers and enables the load balancer to instantly handle them. Our trace-driven experiments on a simulator show the effectiveness of our schemes for guaranteeing the SLAs while achieving the multi-objectives.