OCVM: Optimizing the Isolation of Virtual Machines with Open-Channel SSDs.

A longstanding goal of virtual machines (VMs) isolation running on commercial Solid State Drives (SSDs) is to avoid performance degradation which could be quite severe in certain cases. However, it has been a challenge due to the limitations of the traditional flash translation layer (FTL). We propose OCVM, a novel storage stack that optimizes the isolation of VMs in a multiple VMs environment. By providing channel-granular and block-granular isolation for VMs, OCVM significantly reduces storage internal resource conflicts and eases the pressure of garbage collection (GC). To achieve good VM isolation as well as hardware utilization, OCVM applies a dynamic allocation mechanism for the underlying storage resources of the open-channel SSD (OCSSD). The evaluation results demonstrate that the average execution time of data-intensive applications on OCVM shortens by 28%, compared to those on a baseline system. In addition, OCVM achieves better GC efficiency by reducing the frequency of data migration.