Block storage virtualization with commodity secure digital cards

Smartphones, tablets and other mobile platforms typically accommodate bulk data storage with low-cost, FAT-formatted Secure Digital cards. When one uses a mobile device to run a full-system virtual machine (VM), there can be a mismatch between 1) the VM's I/O mixture, security and reliability requirements and 2) the properties of the storage media available for VM block storage and checkpoint images. To resolve this mismatch, this paper presents a new VM disk image format called the Logging Block Store (LBS). After motivating the need for a new format, LBS is described in detail with experimental results demonstrating its efficacy. As a result of this work, recommendations are made for future optimizations throughout the stack that may simplify and improve the performance of storage virtualization systems on mobile platforms.