HyZNS

 _   _ __   __     ______ ______ __  __ _    _ 
| | | |\ \ / /    |  ____|  ____|  \/  | |  | |
| |_| | \   /     | |__  | |__  | \  / | |  | |
|  _  |  | |   +  |  __| |  __| | |\/| | |  | |
| | | |  | |      | |    | |____| |  | | |__| |
|_| |_|  |_|      |_|    |______|_|  |_|\____/  -- A QEMU-based and DRAM-backed NVMe SSD Emulator

Contact Information

Maintainer: Doeun Kim, Email: doeun96@hanyang.ac.kr

Developer: Junmo Seong, Email: wnsah814@hanyang.ac.kr Jinyoung Kim, Email: ffff4001@hanyang.ac.kr

Contributor: Junill Jang, Email: jang1161@hanyang.ac.kr

Project Description (What is FEMU?)

                        +--------------------+
                        |    VM / Guest OS   |
                        |                    |
                        |                    |
                        |  NVMe Block Device |
                        +--------^^----------+
                                 ||
                              PCIe/NVMe
                                 ||
  +------------------------------vv------------------------------+
  |  +---------+ +---------+ +---------+ +---------+ +--------+  |
  |  | Blackbox| |  .....  | | ZNS-SSD | |  .....  | | HY-ZNS |  |
  |  +---------+ +---------+ +---------+ +---------+ +--------+  |
  |                    FEMU NVMe SSD Controller                  |
  +--------------------------------------------------------------+

Briefly speaking, FEMU is a fast, accurate, scalable, and extensible NVMe SSD Emulator. Based upon QEMU/KVM, FEMU is exposed to Guest OS (Linux) as an NVMe block device (e.g. /dev/nvme0nX). It supports emulating different types of SSDs:

• Blackbox mode (BBSSD) with FTL managed by the device (like most of current commercial SSDs). A page-level mapping based FTL is included.

• ZNS mode (ZNSSD), exposing NVMe Zone interface for the host to directly read/write/append to the device following certain rules.

• HY-ZNS mode (HYZNS), (a.k.a. Hybrid ZNS) Some Zone are managed with host FTL,
  and the others are exposing NVMe Zone interface for the host to directly read/write/append to the device following certain rules.

Run FEMU

0. Minimum Requirement

• Run FEMU on a physical machine, not inside a VM (if the VM has nested virtualization enabled, you can also give it a try, but FEMU performance will suffer, this is not recommended.)

• At least 8 cores and 12GB DRAM in the physical machine to enable seamless run of the following default FEMU scripts emulating a 4GB SSD in a VM with 4 vCPUs and 4GB DRAM.

• If you intend to emulate a larger VM (more vCPUs and DRAM) and an SSD with larger capacity, make sure refer to the resource provisioning tips here.

• For more details, please check out the FEMU wiki.

1. Compile FEMU and Boot the Guest VM (host side)

cd femu
mkdir build-femu && cd build-femu
cp ../femu-scripts/femu-copy-scripts.sh . && ./femu-copy-scripts.sh
sudo ./pkgdep.sh    # one-time: build dependencies
./femu-compile.sh
./run-hyzns.sh      # boots the guest VM with the HyZNS device (8x4 geometry)

All remaining steps run inside the guest VM.

2. Paper Experiments (guest side)

Every figure of the paper is reproduced with a single command. Each experiments/<figure>/run.sh pins the exact parameters used for the published data, runs the workload, and chains all post-processing, so the plot-ready CSVs and preview figures land in the printed output path:

See experiments/README.md for the full figure-to-command map, expected runtimes, and the in-VM build steps.