ConZone is a versatile software-defined consumer-level virtual zoned device. It is developed based on NVMeVirt, which is implemented as a Linux kernel module.
Further details on the design and implementation of ConZone can be found in the following papers.
(DATE 2025) ConZone: A Zoned Flash Storage Emulator for Consumer Devices
Please feel free to contact us at [dingcuiy@gamil.com] if you have any questions or suggestions.
- Requirement: Linux Kernel v6.x and above (Recommended: v6.12.16 or any other stable version)
- My Environment: Ubuntu 22.04.5 LTS (Kernel 6.12.16)
- Note: If you use another kernel version, the Kernel Code/Data might occupy the reserved space. For the reason, please see snu-csl/nvmevirt#60 (comment).
Edit the GRUB_CMDLINE_LINUX in /etc/default/grub. Separate multiple options with a space.
NVMeVirt is a DRAM-based emulator that requires reserving a certain amount of physical memory. The reserved size corresponds to the storage device's capacity plus overhead.
For example, if your server has 160GiB of physical memory and you want to emulate a 64GiB flash storage device, you might reserve 79GiB (64GiB + SLC buffer overhead) and the start address is 82 GiB.
Add the following to your GRUB config:
GRUB_CMDLINE_LINUX="memmap=79G\\\$82G"
(Note: memmap=nnG$ssG reserves nn GB of memory starting at address ss GB. The backslash \ is often required to escape the $ in certain config environments, verify based on your distribution.)
P.S. After updating the grub and rebooting, you can verify if the reservation was successful by checking the current contiguous memory layout with sudo cat /proc/iomem.
To prevent NVMeVirt from interfering with applications, you can reserve dedicated cores for the dispatcher and I/O threads:
GRUB_CMDLINE_LINUX="memmap=79G\$82G isolcpus=7,8"
sudo update-grub
sudo rebootgit clone git@github.com:DingcuiYu/ConZone.gitcd f2fs-tools-1.14.0
./autogen.sh
./configure --prefix=$(pwd)/build
make
make install
cd ..cd ConZone
make -j `nproc`A successful compilation will look like this: (P.S. zonelinux-6.12.16 is my custom kernel)
make -C /lib/modules/6.12.16-custom+/build M=/home/lab/mnt/home/lab/ydc/emulators/public/ConZone modules
make[1]: Entering directory '/home/lab/mnt/home/lab/ydc/linux/zonelinux-6.12.16'
warning: the compiler differs from the one used to build the kernel
The kernel was built by: gcc (Ubuntu 12.3.0-1ubuntu1~22.04) 12.3.0
You are using: gcc (Ubuntu 12.3.0-1ubuntu1~22.04.2) 12.3.0
CC [M] /home/lab/mnt/home/lab/ydc/emulators/public/ConZone/main.o
CC [M] /home/lab/mnt/home/lab/ydc/emulators/public/ConZone/pci.o
CC [M] /home/lab/mnt/home/lab/ydc/emulators/public/ConZone/admin.o
CC [M] /home/lab/mnt/home/lab/ydc/emulators/public/ConZone/io.o
CC [M] /home/lab/mnt/home/lab/ydc/emulators/public/ConZone/dma.o
CC [M] /home/lab/mnt/home/lab/ydc/emulators/public/ConZone/ssd.o
CC [M] /home/lab/mnt/home/lab/ydc/emulators/public/ConZone/zns_ftl.o
CC [M] /home/lab/mnt/home/lab/ydc/emulators/public/ConZone/zns_read_write.o
CC [M] /home/lab/mnt/home/lab/ydc/emulators/public/ConZone/zms_read_write.o
CC [M] /home/lab/mnt/home/lab/ydc/emulators/public/ConZone/zns_mgmt_send.o
CC [M] /home/lab/mnt/home/lab/ydc/emulators/public/ConZone/zns_mgmt_recv.o
CC [M] /home/lab/mnt/home/lab/ydc/emulators/public/ConZone/channel_model.o
CC [M] /home/lab/mnt/home/lab/ydc/emulators/public/ConZone/conv_ftl.o
CC [M] /home/lab/mnt/home/lab/ydc/emulators/public/ConZone/simple_ftl.o
CC [M] /home/lab/mnt/home/lab/ydc/emulators/public/ConZone/pqueue/pqueue.o
LD [M] /home/lab/mnt/home/lab/ydc/emulators/public/ConZone/nvmev.o
MODPOST /home/lab/mnt/home/lab/ydc/emulators/public/ConZone/Module.symvers
CC [M] /home/lab/mnt/home/lab/ydc/emulators/public/ConZone/nvmev.mod.o
CC [M] /home/lab/mnt/home/lab/ydc/emulators/public/ConZone/.module-common.o
LD [M] /home/lab/mnt/home/lab/ydc/emulators/public/ConZone/nvmev.ko
BTF [M] /home/lab/mnt/home/lab/ydc/emulators/public/ConZone/nvmev.ko
make[1]: Leaving directory '/home/lab/mnt/home/lab/ydc/linux/zonelinux-6.12.16'
Since ConZone's flash storage includes an invisible SLC buffer, simulating a 64GiB SSD requires 64GiB + [SLC buffer size] + 1 MiB of memory.
Use the provided script to calculate sizes and generate the insmod command:
python3 scripts/size.pyFollow the interactive prompts to modify ssd_config.h.
Configuration Option Reference:
| Prompt | Corresponding to the option following #elif (BASE_SSD == CONZONE_PROTOTYPE) in ssd_config.h |
Meaning or Effect |
|---|---|---|
| Select prototype (conzone/zns) [default: conzone]: | None. Corresponds to the Kbuild directive : # Select one of the targets to build, CONFIG_NVMEVIRT_CONZONE := y for conzone;CONFIG_NVMEVIRT_ZNS := y for zns |
Use storage prototype |
| Memmap start address [default: 102G]: | None. Corresponds to the starting address of reserved memory in /etc/default/grub. For example, if GRUB_CMDLINE_LINUX="memmap=79G\$82G isolcpus=7,8", the starting address is 82G |
NVMeVirt requires determining the memory location for simulation. The script automatically reads /etc/default/grub to obtain the default value |
| Flash type (TLC/QLC) [default: TLC]: | CELL_MODE: CELL_MODE_TLC: TLC CELL_MODE_QLC: QLC |
Affects flash block size, zone size, and zone capacity. The ZNS protocol prohibits zone sizes that are not powers of 2. Using TLC may cause block sizes to violate this constraint. |
| Interface type (block/zoned) [default: zoned]: | NS_SSD_TYPE_1: SSD_TYPE_CONZONE_BLOCK: block SSD_TYPE_CONZONE_ZONED: zone |
Interface type for the data area. Setting block interface enables comparison. |
| Block size [default: 33M]: | BLK_SIZE: MB(66ULL): default size for TLC MB(68ULL): default size for QLC |
Flash block size |
| Planes per Superblock (Parallelism) [default: 16]: | PLNS_PER_ZONE : i.e., DIES_PER_ZONE * PLNS_PER_LUN |
Determines zone capacity |
| pSLC superblocks for data [default: 4]: | DATA_pSLC_INIT_BLKS |
Number of superblocks for SLC buffers in namespace 1 (data zone). Note that the SLC superblock size is 1/3 that of TLC superblocks and 1/4 that of QLC superblocks. |
| Data namespace size [default: 32G]: | None, must be entered manually | Size of the user-visible disk (data zone) |
| Meta namespace size [default: 0K]: | LOGICAL_META_SIZE: Enter 0 to automatically calculate the appropriate size and modify ssd_config.h |
Logical space size of the metadata namespace. Note: Ensure that during formatting, namespace 0 precisely corresponds to the F2FS metadata namespace. |
| Meta OP ratio [default: 0.07]: | OP_AREA_PERCENT: Automatically calculates PHYSICAL_META_SIZE |
Reserves space for the metadata area and the data area after using the block interface. Ensure reserved space ≥ 7% of visible space. |
The script will output a summary and an insmod command at the end, for example:
----------------------------------
Summary:
Prototype: conzone
Flash: TLC | Interface: zoned
Super Block: 528M
Meta Size: 2G Phy Meta Size: 7392M
Insmod Command:
sudo insmod ./nvmev.ko memmap_start=102G memmap_size=44881M cpus=37,39You will need to paste it into the INSMOD_CMD variable in scripts/mount.py.
Open scripts/mount.py and perform the following:
-
Paste the
insmodcommand intoINSMOD_CMD. -
Modify
WORK_DIRto your absolute directory path. -
If formatting is needed, adjust
MKFS_CMDaccording to your interface (zoned vs block).
Option A: Test Bare Disk (Raw Device)
sudo python3 scripts/mount.py rawdeviceOption B: Mount with Filesystem
sudo python3 scripts/mount.pyIf successful, the command will complete silently. You can then use lsblk to see the emulated storage:
nvme2n1 259:9 0 256M 0 disk
nvme2n2 259:10 0 4G 0 disk Logs: You can check boot logs in log/insmod_dmesg, format logs in log/mkfs_dmesg, and mount logs in log/mount_dmesg.
You can now test performance using FIO, Mobibench, or other standard tools.
- Batch Testing: A helper script is available at
scripts/exp.py. - Mobibench: Source code is included in the repository.
If you tested a bare disk:
sudo python3 scripts/umount.py rawdeviceIf you tested with a filesystem:
sudo python3 scripts/umount.pyAfter unmounting/removing the module, statistics are dumped to the kernel log. View them in log/rmmod_dmesg.
[2707784.596989] NVMeVirt: Version 1.10 for >> CONZONE SSD Prototype <<
[2707784.597005] NVMeVirt: Storage: 0x1480100000-0x16a8100000 (8832 MiB)
[2707784.621870] NVMeVirt: -------------META PARAMS----------------
[2707784.621874] NVMeVirt: [Logical Space] 256 MiB [Physical Space] 1152 MiB
[2707784.621876] NVMeVirt: [Write Buffer Size] 512 KiB [# of Write Buffer] 1
[2707784.621878] NVMeVirt: [# of pSLC Superblocks] 9
[2707784.621882] NVMeVirt: [Size of Each Write Buffer] 512 KiB [LPNs per Write Buffer] 128
[2707784.621884] NVMeVirt: ---------zms init block namespace id 0 csi 0 ftl 000000007dcd4479--------------
[2707784.621888] NVMeVirt: ns 0/2: size 256 MiB
[2707784.621890] NVMeVirt: -------------DATA PARAMS (ZONED)----------------
[2707784.621892] NVMeVirt: [Logical Space] 4096 MiB [pSLC Reserved Size] 3584 MiB [Physical Space] 7680 MiB
[2707784.621894] NVMeVirt: [Write Buffer Size] 768 KiB [# of Write Buffer] 6
[2707784.621895] NVMeVirt: [# of pSLC Superblocks] 28
[2707784.621897] NVMeVirt: [Zone Size] 128 MiB [Zone Capacity] 128 MiB [# of Zones] 32
[2707784.621899] NVMeVirt: [Chunk Size] 4 MiB [Logical Pages per Zone] 32768 [Logical Pages per Chunk] 1024
[2707784.621903] NVMeVirt: [Size of Each Write Buffer] 128 KiB [LPNs per Write Buffer] 32
[2707784.621906] NVMeVirt: ---------zms init zoned namespace id 1 csi 2 ftl 000000004a477c6c--------------
[2707784.621908] NVMeVirt: ns 1/2: size 4096 MiB
[2707784.621911] NVMeVirt: ------------SSD PARAMS-----------
[2707784.621913] NVMeVirt: [# of Channels] 2 [Luns per Channel] 2 [Planes per Lun] 1 [Blocks per Plane] 69 [Logical Pages per Block] 8192
[2707784.621915] NVMeVirt: [Logical Page Size] 4 KiB [Flash Page Size] 32 KiB [Oneshot Page Size] 128 KiB
[2707784.621917] NVMeVirt: [Total pSLC Superblocks] 37 [Meta pSLC Superblocks] 9 [Meta Normal Superblocks] 0
[2707784.621919] NVMeVirt: [Total pSLC Size] 4736 MiB [Meta pSLC Size] 1152 MiB
[2707784.621921] NVMeVirt: [Total pSLC Capacity] 1184 MiB [Meta pSLC Capacity] 288 MiB
[2707784.621922] NVMeVirt: [Logical Pages per pSLC Block] 2048 [Logical Pages per pSLC Line] 8192
[2707784.621924] NVMeVirt: Total Capacity(GiB,MiB)=8,8832 chs=2 luns=4 lines=69 blk-size(MiB,KiB)=32,32768 line-size(MiB,KiB)=128,131072
[2707784.621928] NVMeVirt: ----------------------------
[2707784.689711] NVMeVirt: [chmodel_init] bandwidth 1600 max_credits 52 tx_time 76
[2707784.754781] NVMeVirt: [chmodel_init] bandwidth 1600 max_credits 52 tx_time 76
[2707784.754807] NVMeVirt: [chmodel_init] bandwidth 3000 max_credits 98 tx_time 40
[2707784.756210] NVMeVirt: [# of L2P Entries (cached/all)] 261120 / 65536 [Evict Policy] 1 [Pre Read Pages] 0
[2707784.756218] NVMeVirt: pqueue: Copyright (c) 2014, Volkan Yazıcı <volkan.yazici@gmail.com>. All rights reserved.
[2707784.756222] NVMeVirt: Line id 0 -> Block id 0 nand type 1
[2707784.756224] NVMeVirt: Line id 1 -> Block id 1 nand type 1
[2707784.756225] NVMeVirt: Line id 2 -> Block id 2 nand type 1
[2707784.756227] NVMeVirt: Line id 3 -> Block id 3 nand type 1
[2707784.756228] NVMeVirt: Line id 4 -> Block id 4 nand type 1
[2707784.756230] NVMeVirt: Line id 5 -> Block id 5 nand type 1
[2707784.756231] NVMeVirt: Line id 6 -> Block id 6 nand type 1
[2707784.756233] NVMeVirt: Line id 7 -> Block id 7 nand type 1
[2707784.756234] NVMeVirt: Line id 8 -> Block id 8 nand type 1
[2707784.756236] NVMeVirt: Line Management: [# of Top Level Lines] 9 [Interleave Lines] 9 [pSLC Lines] 9
[2707784.756238] NVMeVirt: Line Management: [Free Normal Lines] 0 [Free pSLC Lines] 9
[2707784.756240] NVMeVirt: prepared slc wp for USER IO, line id 0 blk id 0
[2707784.756242] NVMeVirt: prepared slc wp for GC IO, line id 1 blk id 1
[2707784.756244] NVMeVirt: [Total Lines] 9 [pSLC Lines] 9 [Normal lines] 0
[2707784.756844] NVMeVirt: [# of RMap Entries] 294912
[2707784.756848] NVMeVirt: [Num Aggs] 1
[2707784.756850] NVMeVirt: --------------- realize block namespace 0 ssd 0000000002f829ab--------------
[2707784.760462] NVMeVirt: [# of L2P Entries (cached/all)] 261120 / 1048576 [Evict Policy] 1 [Pre Read Pages] 0
[2707784.760473] NVMeVirt: Line id 0 -> Block id 9 nand type 1
[2707784.760475] NVMeVirt: Line id 1 -> Block id 10 nand type 1
... [Truncated: line and block mapping information]
[2707784.760561] NVMeVirt: Line Management: [# of Top Level Lines] 60 [Interleave Lines] 60 [pSLC Lines] 28
[2707784.760563] NVMeVirt: Line Management: [Free Normal Lines] 32 [Free pSLC Lines] 28
[2707784.760565] NVMeVirt: prepared normal wp for USER IO, line id 28 blk id 37
[2707784.760567] NVMeVirt: prepared slc wp for USER IO, line id 0 blk id 9
[2707784.760568] NVMeVirt: prepared slc wp for GC IO, line id 1 blk id 10
[2707784.760570] NVMeVirt: [Total Lines] 60 [pSLC Lines] 28 [Normal lines] 32
[2707784.764567] NVMeVirt: [# of RMap Entries] 1966080
[2707784.764576] NVMeVirt: [Num Aggs] 32
[2707784.764578] NVMeVirt: --------------- realize zoned namespace 1 ssd 0000000002f829ab--------------
[2707784.764651] PCI host bridge to bus 0001:10
[2707784.764655] pci_bus 0001:10: root bus resource [io 0x0000-0xffff]
[2707784.764659] pci_bus 0001:10: root bus resource [mem 0x00000000-0x3fffffffffff]
[2707784.764663] pci_bus 0001:10: root bus resource [bus 00-ff]
[2707784.764674] pci 0001:10:00.0: [0c51:0110] type 00 class 0x010802 PCIe Endpoint
[2707784.764680] pci 0001:10:00.0: BAR 0 [mem 0x1480000000-0x1480003fff 64bit]
[2707784.764685] pci 0001:10:00.0: enabling Extended Tags
[2707784.765315] NVMeVirt: Virtual PCI bus created (node 0)
[2707784.765952] NVMeVirt: nvmev_io_worker_0 started on cpu 8 (node 0)
[2707784.766187] NVMeVirt: nvmev_dispatcher started on cpu 7 (node 0)
[2707784.766535] nvme nvme2: pci function 0001:10:00.0
[2707784.770234] nvme nvme2: 1/0/0 default/read/poll queues
[2707784.793018] NVMeVirt: Virtual NVMe device created F2FS-tools: mkfs.f2fs Ver: 1.14.0 (2020-08-24)
Info: Disable heap-based policy
Info: Debug level = 0
Info: Trim is enabled
Info: Host-managed zoned block device:
32 zones, 0 randomly writeable zones
32768 blocks per zone
Info: Segments per section = 64
Info: Sections per zone = 1
Info: sector size = 512
Info: total sectors = 8912896 (4352 MB)
Info: zone aligned segment0 blkaddr: 32768
...
[MISAO] Info: device 0 /dev/nvme2n1 blkaddr[0 - 65535] tt segs 64
[MISAO] Info: device 1 /dev/nvme2n2 blkaddr[65536 - 1114111] tt segs 2048
...
[MISAO] Info: main blkaddr 65536[ 730.483157] NVMeVirt: Init slc wp for USER IO, line id 0 blk id 0
[ 730.573318] NVMeVirt: Init slc wp for USER IO, line id 0 blk id 7
[ 730.583731] F2FS-fs (nvme2n1): Mount Device [ 0]: /dev/nvme2n1, 512, 0 - 7ffff
[ 730.583759] F2FS-fs (nvme2n1): Mount Device [ 1]: /dev/nvme2n2, 16384, 80000 - 87ffff (zone: Host-managed)
[ 730.588474] F2FS-fs (nvme2n1): Found nat_bits in checkpoint
[ 730.708448] F2FS-fs (nvme2n1): Mounted with checkpoint version = 2b7a1171
[2709034.940583] NVMeVirt: -------------MISAO SSD statistic info-----------
[2709034.940593] NVMeVirt: [Channel 0 Lun 0] [Max CMD Queue Depth] 4
[2709034.940601] NVMeVirt: [Channel 0 Lun 1] [Max CMD Queue Depth] 4
[2709034.940607] NVMeVirt: [Channel 1 Lun 0] [Max CMD Queue Depth] 4
[2709034.940613] NVMeVirt: [Channel 1 Lun 1] [Max CMD Queue Depth] 4
[2709035.119993] NVMeVirt: ------------MISAO--device 0 statistic info-----------
[2709035.119997] NVMeVirt: [# of Zone Resets] 0 [# of Zone Writes] 0
[2709035.119999] NVMeVirt: [# of Host Read Requests] 161
[2709035.120001] NVMeVirt: [# of Host Write Requests] 62
[2709035.120002] NVMeVirt: [# of Host Flush Requests] 4
[2709035.120004] NVMeVirt: [Host Read Pages] 846
[2709035.120006] NVMeVirt: [L2P Miss Rate] (0/63) [WB Hits] 0 [Unmapped Read Cnt] 783
[2709035.120008] NVMeVirt: [WAF] (3104/3104) [Migrated Logical Pages] 0
[2709035.120010] NVMeVirt: [# of Normal Line Earse] 0 [# of pSLC Line Erase] 0
[2709035.120012] NVMeVirt: [# of Garbage Collection] 0
[2709035.120013] NVMeVirt: [# of Early Flush] 4
[2709035.120015] NVMeVirt: [pSLC lines] 7/0/0/9 [normal lines] 0/0/0/0 (free/full/victim/all)
[2709035.120017] NVMeVirt: [# of inplace update] 279
[2709035.120833] NVMeVirt: ------------MISAO--device 1 statistic info-----------
[2709035.120837] NVMeVirt: [# of Zone Resets] 0 [# of Zone Writes] 0
[2709035.120839] NVMeVirt: [# of Host Read Requests] 104
[2709035.120841] NVMeVirt: [# of Host Write Requests] 2
[2709035.120843] NVMeVirt: [# of Host Flush Requests] 1
[2709035.120845] NVMeVirt: [Host Read Pages] 530
[2709035.120847] NVMeVirt: [L2P Miss Rate] (0/3) [WB Hits] 0 [Unmapped Read Cnt] 527
[2709035.120849] NVMeVirt: [WAF] (2/2) [Migrated Logical Pages] 0
[2709035.120851] NVMeVirt: [# of Normal Line Earse] 0 [# of pSLC Line Erase] 0
[2709035.120853] NVMeVirt: [# of Garbage Collection] 0
[2709035.120855] NVMeVirt: [# of Early Flush] 2
[2709035.120857] NVMeVirt: [pSLC lines] 26/0/0/28 [normal lines] 31/0/0/32 (free/full/victim/all)
[2709035.120860] NVMeVirt: [# of inplace update] 0
[2709035.144637] NVMeVirt: Virtual NVMe device closedNVMeVirt is offered under the terms of the GNU General Public License version 2 as published by the Free Software Foundation. More information about this license can be found here.
Priority queue implementation pqueue/ is offered under the terms of the BSD 2-clause license (GPL-compatible). (Copyright (c) 2014, Volkan Yazıcı volkan.yazici@gmail.com. All rights reserved.)
