Dual-Mode SSD Architecture for Next- Generation Hyperscale Data Centers Feng Zhu Alibaba Group 2018 Storage Developer Conference. © Alibaba Group. All Rights Reserved. 1 Challenges of hyperscale data centers  Diversified, fast-changing workloads Performance  Continuous pressure for TCO and supply improvement  Demand for “white box” of I/O path - Service Flexibility more control and determinism  Quick response to issues and feature requests  Demand for hardware/software co- White TCO optimization Box 2018 Storage Developer Conference. © Alibaba Group. All Rights Reserved. 2 AliFlash_Alibaba’s self-developed SSDs AliFlash V1 AliFlash V2 AliFlash V3 • High performance • NVMe U.2 SSD • Dual-mode SSD with PCIe SSD open channel • Customization for • Host based FTL. applications • Deep optimization Control on SW/HW for applications • Cost down by 20% • >20k devices serving • Being productized in Alibaba data centers 2016 2017 2018 2018 Storage Developer Conference. © Alibaba Group. All Rights Reserved. 3 First Productionized Open Channel SSD  Alibaba’s self-developed Open Channel SSD - AliFlash V3  Deployment ongoing in Alibaba data centers  Major milestone since the announcement of Alibaba’s Open Channel SSD Architecture in FAST’2018  Collaborating with multiple SSD vendors to build an ecosystem 2018 Storage Developer Conference. © Alibaba Group. All Rights Reserved. 4 Why open channel  New SSD architecture for next-generation data centers Application 1 Application 2 Application 3  Enable hardware/software co-optimization  Maximum flexibility for different workloads Fusion Engine Software  Generic block device Alibaba Open Channel SSD Platform  Customized FTL Open Channel Mode Device Mode  Deep integration with applications Alibaba Open Channel SSD Specification  Reduce time & complexity of SSD qualification Alibaba Open Channel SSD (AOC SSD)  New media ready: QLC NAND, 3D X- point, SCM, ... 2018 Storage Developer Conference. © Alibaba Group. All Rights Reserved. 5 Alibaba Open Channel Architecture  Open Channel mode  Direct access to the physical media, and max utilization of the media capability  Fully control of the data placement and I/O scheduling  FTL/GC customization based on application I/O pattern -> reduced WA 2018 Storage Developer Conference. © Alibaba Group. All Rights Reserved. 6 Customization for Alibaba data centers Requirement analysis In-house Applications developed storage solutions SW/HW SW/HW co- co-design optimization 2018 Storage Developer Conference. © Alibaba Group. All Rights Reserved. 7 © 2017 Alibaba Group Alibaba Open Channel SSD Software  Host-side software stack developed by Alibaba  Kernel-space AOC SSD Driver + Block Device FTL  User-space AOC SSD Driver integrated with Alibaba’s Fusion Engine software  User-space customized FTL solutions  Management, monitoring and test tools 2018 Storage Developer Conference. © Alibaba Group. All Rights Reserved. 8 Kernel-space AOC SSD Solution Application  Work like generic block device  Covers most of the legacy use Fusion Engine User Space File System cases  Equivalent performance and AIO functionality as standard NVMe SSD  Customized improvements and AOC SSD Kernel-Space Driver & FTL extensions (e.g. scheduling & QoS) Alibaba Open Channel SSD 2018 Storage Developer Conference. © Alibaba Group. All Rights Reserved. 9 User-space AOC SSD Solution  Entire I/O path in user space - low Application software overhead Fusion Engine User Space User Space  Deep integration with application - full File System KV Engine benefits from hardware/software co- AOC SSD User Space FTL optimization Solutions  Optimize data placement, coordinated AOC SSD User Space Driver background tasks (garbage collection)  Customized FTL solutions (e.g. Object Alibaba Open Channel SSD SSD) 2018 Storage Developer Conference. © Alibaba Group. All Rights Reserved. 10