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Flash-based key-value caching is becoming popular in data centers for providing high-speed key-value services. These systems adopt slab-based space management on flash and provide a low-cost solution for key-value caching. However, optimizing cache efficiency for flash-based key-value cache systems is highly challenging, due to the huge number of key-value items and the unique technical constraints

Regular file server upgrades are indispensable to improve performance, robustness, and power consumption. In upgrading file servers, it is crucial to quickly migrate file-sharing services between heterogeneous servers with little downtime while minimizing performance interference. We present a practical quick file server migration scheme based on the postcopy approach that defers file copy until after

Erasure codes in large-scale storage systems allow recovery of data from a failed node. A recently developed class of codes, locally repairable codes (LRCs), offers tradeoffs between storage overhead and repair cost. LRCs facilitate efficient recovery scenarios by adding parity blocks to the system. However, these additional blocks may eventually increase the number of blocks that must be reconstructed

For a decade, the Ceph distributed file system followed the conventional wisdom of building its storage backend on top of local file systems. This is a preferred choice for most distributed file systems today, because it allows them to benefit from the convenience and maturity of battle-tested code. Ceph’s experience, however, shows that this comes at a high price. First, developing a zero-overhead

File systems are too large to be bug free. Although handwritten test suites have been widely used to stress file systems, they can hardly keep up with the rapid increase in file system size and complexity, leading to new bugs being introduced. These bugs come in various flavors: buffer overflows to complicated semantic bugs. Although bug-specific checkers exist, they generally lack a way to explore

Data encryption and authentication are essential for secure non-volatile memory (NVM). However, the introduced security metadata needs to be atomically written back to NVM along with data, so as to provide crash consistency, which unfortunately incurs high overhead. To support fine-grained data protection and fast recovery for a secure NVM system without compromising the performance, we propose ShieldNVM

SSD has been playing a significantly important role in caching systems due to its high performance-to-cost ratio. Whereas under social network workloads, large number of total photos are accessed only once whereas they are still swapped in and out of the cache. Therefore, if we can predict this kind of photos proactively and prevent them from entering the cache, we can eliminate unnecessary SSD cache

Existing local file systems, designed to support a typical single-file access mode only, can lead to poor performance when accessing a batch of files, especially small files. This single-file mode essentially serializes accesses to batched files one by one, resulting in a large number of non-sequential, random, and often dependent I/Os between file data and metadata at the storage ends. Such access

Emerging byte-addressable persistent memory technologies are expected to break the boundaries between memory and storage devices. Byte-addressable persistent memory will open up new opportunities to re-design the entire system software stack and to enable storage-less systems. In this work, we propose {\it $B^3$-tree} for byte-addressable persistent memory and show how every single 8-byte write operation

As semiconductor technology has advanced, many storage systems have begun to use non-volatile memories as storage media. The organization and architecture of storage controllers have become more complex to meet various design requirements in terms of performance, response time, quality of service (QoS), etc. In addition, due to the evolution of memory technology and the emergence of new applications

Many file-system applications such as defragmentation tools, file system checkers or data recovery tools, operate at the storage layer. Today, developers of these file-system aware storage applications require detailed knowledge of the file-system format, which requires significant time to learn, often by trial and error, due to insufficient documentation or specification of the format. Furthermore