Overcome the GC-Induced Performance Variability in SSD-Based RAIDs With Request Redirection
Overcome the GC-Induced Performance Variability in SSD-Based RAIDs With Request Redirection
复制标题
通过请求重定向克服基于 SSD 的 RAID 中 GC 引起的性能变化
DOI：
10.1109/tcad.2018.2834407
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发表时间：
2019-05-01
影响因子：
2.9
通讯作者：
Li, Kuan-Ching
中科院分区：
文献类型：
--
作者：
Wu, Suzhen;Li, Haijun;Li, Kuan-Ching
随着数据量的爆炸式增长，I/O瓶颈已经成为大数据分析面临的一个日益严峻的挑战。基于闪存的ssd有望取代硬盘驱动器。但是，在SSD上进行垃圾收集操作会对SSD的性能产生较大的影响，从而导致基于SSD的raid的性能不稳定。为了解决这个问题，我们提出了请求重定向（RR），利用SSD和基于SSD的raid中的热备SSD的非对称读写性能特征来减轻gc引起的性能变化。RR通过在基于SSD的raid中重构来自同一条带的其他SSD的读数据，来处理当前处于GC状态的SSD的读请求。对于进入处于GC状态的SSD盘的写数据，RR会将写数据临时保存在热备的SSD盘上，同时在基于SSD盘的raid中更新相应的奇偶校验。对RR原型的大量评估表明，与局部GC和全局GC方案相比，RR方案显著降低了平均响应时间，减轻了性能的可变性。
The I/O bottleneck has become an increasingly daunting challenge for big data analytics along with the explosive growth in data volume. Flash-based SSDs become promising to replace the hard disk drives. However, garbage collection (GC) operations in SSDs have a significant impact on the SSD performance, thus leading to performance variability in SSD-based RAIDs. To address this problem, we propose request redirection (RR) by exploiting the asymmetric read-write performance characteristics of SSDs and the hot-spare SSD in SSD-based RAIDs to alleviate the GC-induced performance variability. RR services the incoming read requests to the SSD currently in GC state by reconstructing the read data from other SSDs in the same stripe within SSD-based RAIDs. For the incoming write data to the SSD in the GC state, RR temporarily stores the write data on the hot-spare SSD and concurrently updates the corresponding parity in the SSD-based RAIDs. Extensive evaluations on the RR prototype show that the RR scheme significantly reduces the average response time and alleviates the performance variability, compared with the local GC and global GC schemes.