Open Source Summit + Embedded Linux Conference Europe 2020

The QEMU generic machine emulator and virtualizer includes a wide range of emulated devices. These devices can be very useful for debugging a software stack and for prototyping new features that is yet to be available in hardware and firmware. In this technical talk we focus on "prototyping new features" in the emulated NVMe device. We will go through the core event loop of the upstream device and explore how the recently ratified Namespace Types and Zoned Namespaces NVMe Technical Proposals can be implemented. Finally, we will design a custom (non-spec) command and go through a prototype implementation. We will then discuss how such a QEMU prototype implementation helps when developing the associated software stack and see how the feature can be tested and verified from a Linux host.

All-Flash Array is replacing traditional hard disk drive to become the main data storage medium for enterprises and cloud data centers. However, flash memory has the inherent drawbacks of low performance for random write access and lifespan. In this talk, Vicki will introduce the open source All-Flash Array software-defined storage system, SOFA (Software Orchestrated Flash Array), developed by ITRI to free the flash memory from these two constraints with intelligent algorithm and system optimization. SOFA is to build a system software running on a storage server equipped with a flash memory disk array. Its main advantages are to provide high data protection while also achieving high random access. The system provides a block device for users to read and write data, and data will be stored distributedly across all SSDs by RAID5 protection. The technology breaks through the performance barrier, as exhibited by conventional approach of hardware or software based RAID5, and simultaneously doubles the lifespan of disk array by proprietary Global Wear Leveling mechanism.