Browsing by Subject "Storage Systems"
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Item Integrating flash memory into the storage hierarchy.(2010-10) Debnath, Biplob KumarWith the continually accelerating growth of data, the performance of storage systems is increasingly becoming a bottleneck to improving overall system performance. Many applications, such as transaction processing systems, weather forecasting, large-scale scientific simulations, and on-demand services are limited by the performance of the underlying storage systems. The limited bandwidth, high power consumption, and low reliability of widely used magnetic disk-based storage systems impose a significant hurdle in scaling these applications to satisfy the increasing growth of data. These limitations and bottlenecks are especially acute for large-scale high-performance computing systems. Flash memory is an emerging storage technology that shows tremendous promise to compensate for the limitations of current storage devices. Flash memory's relatively high cost, however, combined with its slow write performance and limited number of erase cycles requires new and innovative solutions to integrate flash memory-based storage devices into a high-performance storage hierarchy. The first part of this thesis develops new algorithms, data structures, and storage architectures to address the fundamental issues that limit the use of flash-based storage devices in high-performance computing systems. The second part of the thesis demonstrates two innovative applications of the flash-based storage. In particular, the first part addresses a set of fundamental issues including new write caching techniques, sampling-based RAM-space efficient garbage collection scheme, and writing strategies for improving the performance of flash memory for write-intensive applications. This effort will improve the fundamental understanding of flash memory, will remedy the major limitations of using flash-based storage devices, and will extend the capability of flash memory to support many critical applications. On the other hand, the second part demonstrates how flash memory can be used to speed up server applications including Bloom Filter and online deduplication system. This effort will use flash-aware data structures and algorithms, and will show innovative uses of flash-based storage.Item Storage System Designs with Emerging Storage Technologies(2020-01) Zhang, BaoquanIn modern data centers, the volume of data has grown to an enormous size with an incredible speed due to the flourish of the Internet, mobile network, and the Internet of Things (IoT). Storage systems play a critical role under different scenarios, e.g., machine learning pipeline, interactive data analysis, data storage service, etc. Applications have to meet with very high requirements in the aspects of performance, capacity, and reliability. However, the I/O performance of storage systems suffer from the long-latency of storage devices. Besides, the data area density of storage devices has reached a bottleneck. Thus, it becomes difficult to increase the capacity of storage systems further. At last, silent data corruption happens more frequently than we expect. Traditional methods, e.g., replica, erasure code, etc., are not sufficient to ensure data reliability anymore. To address these challenges of performance, capacity, and data reliability in storage systems, storage vendors have proposed new storage technologies/devices. Firstly, Non-Volatile Memory (NVM) is a persistent memory that provides memory-speed data persistence and byte-addressable data accesses. Secondly, Shingled Magnetic Recording (SMR) is a promising layout to increase data area density further with existing magnetic recording technologies. At last, T10 Protection Information (T10-PI) drives are proposed against data corruption. However, current storage systems need to be optimized or even redesigned to leverage the advantages of these new storage technologies/devices. This thesis introduces four complemented research topics targeting designing new storage systems using NVM, SMR drives, PI-capable drives, and hybrid systems with NVM and storage devices, respectively. NVLSM is a key-value store using Log-Structured Merge Tree (LSM-Tree) on NVM systems. Idler is a mechanism to control the I/O workload to minimize the tail response time of an SMR drive. Idler artificially induces idle cleanings to avoid expensive blocking cleanings. DIX-aware RAID improves the data integrity in Linux software RAID using T10-PI against any data corruption during data transmission and persistence. Finally, PMDB is a new key-value store on systems with both NVM and traditional storage devices to achieve performance and capacity simultaneously.