As flash-based solid-state drive (SSD) becomes more prevalent because of the rapid fall in price and the significant increase in capacity, customers expect better data services than traditional disk-based systems. However, the order of magnitude performance provided and new characteristics of flash require a rethinking of data services. For example, backup and recovery is an important service in a database system since it protects data against unexpected hardware and software failures. To provide backup and recovery, backup/recovery tools or backup/recovery methods by operating systems can be used. However, the tools perform time-consuming jobs, and the methods may negatively affect run-time performance during normal operation even though high-performance SSDs are used. To handle these issues, we propose an SSD-assisted backup/recovery scheme for database systems. Our scheme is to utilize the characteristics (e.g., out-of-place update) of flash-based SSD for backup/recovery operations. To this end, we exploit the resources (e.g., flash translation layer and DRAM cache with supercapacitors) inside SSD, and we call our SSD with new backup/recovery functionality BR-SSD. We design and implement the functionality in the Samsung enterprise-class SSD (i.e., SM843Tn) for more realistic systems. Furthermore, we exploit and integrate BR-SSDs into database systems (i.e., MySQL) in replication and redundant array of independent disks (RAID) environments, as well as a database system in a single BR-SSD. The experimental result demonstrates that our scheme provides fast backup and recovery but does not negatively affect the run-time performance during normal operation.

中文翻译：

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SSD辅助数据库系统备份与恢复的设计与实现

随着基于闪存的固态硬盘 (SSD) 由于价格的快速下降和容量的显着增加而变得越来越流行，客户期望比传统的基于磁盘的系统更好的数据服务。然而，提供的数量级性能和闪存的新特性需要重新考虑数据服务。例如，备份和恢复是数据库系统中的一项重要服务，因为它可以保护数据免受意外硬件和软件故障的影响。为了提供备份和恢复，可以使用操作系统的备份/恢复工具或备份/恢复方法。然而，这些工具执行耗时的工作，即使使用高性能 SSD，这些方法也可能对正常操作期间的运行时性能产生负面影响。为了处理这些问题，我们为数据库系统提出了一种 SSD 辅助的备份/恢复方案。我们的方案是利用基于闪存的 SSD 的特性（例如，异地更新）进行备份/恢复操作。为此，我们利用 SSD 内部的资源（例如，闪存转换层和带有超级电容器的 DRAM 缓存），我们将具有新备份/恢复功能的 SSD 称为 BR-SSD。我们在三星企业级 SSD（即 SM843Tn）中设计并实现了更真实的系统功能。此外，我们在复制和独立磁盘冗余阵列 (RAID) 环境中以及单个 BR-SSD 中的数据库系统中开发和集成 BR-SSD 并将其集成到数据库系统（即 MySQL）中。