On-the-Fly Automated Storage Tiering with Caching and both Proactive and Observational Migration
On-the-Fly Automated Storage Tiering with Caching and both Proactive and Observational Migration
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具有缓存以及主动和观察性迁移的动态自动存储分层
DOI：
10.1109/candar.2015.42
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
K. Okamura
中科院分区：
文献类型：
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作者：
Kazuichi Oe;T. Nanri;K. Okamura
由SSD和HDD组成的混合存储系统通过将IO集中区域从HDD移动到SSD来提高用户IO的性能。系统必须识别这些区域并立即将其移动到SSD。我们研究了操作存储服务器的IO集中度，发现了一种类型，它们在存储卷的狭窄区域内持续长达一个小时。狭窄区域是相同的连续区域，或者是平均经过3分钟后移动到相邻区域的区域。此外，它出现在随机逻辑块地址（LBA）。我们决定将这种IO集中称为“游荡IO集中区”（WIOCA）。为了处理这些集中，我们开发了一种动态自动存储分层（OTF-AST），它具有缓存系统以及主动和观察迁移功能。该方法动态地将WIOCA迁移到OTF-AST的SSD，并将其他IO集中移交给缓存。主动迁移功能将候选WIOCA迁移到可能在不久的将来成为一个区域的区域。另一方面，观察迁移功能通过检查用户响应时间来确定HDD开销，并在HDD开销较低时将曾经是但不再是WIOCA一部分的子LUN从SSD迁移到HDD。实验结果表明，我们的方法是113%的速度比Facebook的FlashCache上的微软研究剑桥的工作负载。
A hybrid storage system consisting of SSDs and HDDs improves the performance of user IOs by moving IO concentrated areas from the HDDs to the SSDs. It is important for the system to identify such areas and move them to the SSDs immediately. We studied the IO concentrations of operational storage servers and found one type that they continue for up to an hour within a narrow region of storage volume. The narrow region is either the same continued area or the area which moves to the neighboring after 3 minutes in average had passed. Moreover, it appeared at random logical block addresses (LBAs). We decide to call such IO concentrations Wandering IO Concentrated Areas (WIOCAs). To handle these concentrations, we developed an on-the-fly automated storage tiering (OTF-AST) with a caching system and both proactive and observational migration features. This method dynamically migrates the WIOCAs to the SSD of the OTF-AST and hands over the other IO concentrations to cache. The proactive migration feature migrates candidate WIOCAs to an area that will likely become one in the near future. On the other hand, the observational migration feature determines the HDD overhead by checking the user response time and migrates the sub-LUNs that were but are no longer parts of a WIOCA from the SSD to the HDD when the HDD overhead is low. Experimental results showed that our method was 113% faster than Facebook FlashCache on one of the Microsoft Research Cambridge workloads.