sudo python3 scripts/exp.py
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 the author at [dingcuiy@gamil.com] if you have any questions or suggestions.
- Requirement: v6.10 and above (Recommended: v6.12.16)
- My Environment: Ubuntu 22.04.5 LTS (6.12.16)
- Note: If you use a lower 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 and requires a certain amount of physical memory to be reserved. The reserved size is the size of the storage device.
For example, if the server is equiped with about 160GiB of physical memory and I want to emulate a 64GiB flash storage, I can use:
GRUB_CMDLINE_LINUX="memmap=79G\\\$82G"
Here, a total of 79GiB of memory is reserved because of the user-invisible SLC area.
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 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 user-invisible SLC buffers, emulating a 64GiB SSD requires 64 GiB + [size of SLC buffer] + 1 MiB of memory. The 1 MiB is for the ZNS SSD emulation in NVMeVirt.
To simplify this, ConZone provides a script, scripts/size.py, to help you calculate the sizes.
Usage
python3 scripts/size.pyThis will present you with some interactive options. If the default value is suitable, simply press Enter. Note that the options are case-sensitive.
It is crucial to ensure that the values you enter here match the settings in ssd_config.h.
Here is the meaning of each option:
| Prompt | Corresponding ssd_config.h Option that after#elif (BASE_SSD == CONZONE_PROTOTYPE) |
Meaning or Influence |
|---|---|---|
| Please enter the prototype of the emulator (conzone or zns): [default: conzone]: | None. Corresponds to # Select one of the targets to build in Kbuild. CONFIG_NVMEVIRT_CONZONE := y for conzone; CONFIG_NVMEVIRT_ZNS := y for zns. |
Influences the minimum SLC buffer size. ZNS is a single-medium type with no SLC buffer; conzone currently defaults to at least 4 SLC superblocks. |
| Please enter the start address of memmap (e.g., 82G): [default: 82G]: | None. Corresponds to the starting address of the reserved memory in /etc/default/grub. For example, in GRUB_CMDLINE_LINUX="memmap=79G\\\$82G isolcpus=7,8", the start address is 82G. |
NVMeVirt needs this to locate the memory for emulation. |
| Please enter the flash type (e.g., TLC, QLC): [default: QLC]: | CELL_MODE :CELL_MODE_TLC : TLCCELL_MODE_QLC : QLC |
Influences the flash block size, zone size, and zone capacity. Under the ZNS protocol, zone sizes must be powers of 2, a constraint that TLC might violate. |
| Please enter the interface type (e.g., block, zoned): [default: zoned]: | NS_SSD_TYPE_1 :SSD_TYPE_CONZONE_BLOCK : blockSSD_TYPE_CONZONE_ZONED : zone |
Defines the interface type for the data area; the block interface is useful for comparison. |
| Please enter blcok size (e.g., 2M, 32M): [default: 32M]: | BLK_SIZE ：MB(24ULL) : default size of TLCMB(32ULL) : default size of QLC |
Flash block size. |
| Please enter the number of dies per superblock: [default: 4] | DIES_PER_ZONE : Determined by NAND_CHANNELS and LUNS_PER_NAND_CH, which defaults to 4. |
Determines the zone capacity. |
| Please enter the number of pSLC superblocks for data area: [default: 28]: | DATA_pSLC_INIT_BLKS ：Defaults to 28, which has no special meaning. |
Sets the number of SLC superblocks for the data area (namespace 1). Note that the size of an SLC superblock is 1/3 the size of a TLC superblock and 1/4 the size of a QLC superblock. |
| Please enter the size of data namespace (e.g., 4G): [default: 4G]: | None. | The user-visible storage size. |
| Please enter the size of meta namespace (e.g., 256M, 40M): [default: 256M]: | LOGICAL_META_SIZE ：An empirical value; see below for how to adjust it.Here are some reference values from my practice: For 4GiB storage, 256MiB for zoned interface, 40MiB for block interface. For 64GiB storage, 512MiB for zoned interface, 376MiB for block interface. |
The logical space size for the metadata area, ensuring namespace 0 is exactly the metadata area for F2FS during formatting. |
| Enter the OP ratio for meta area [default: 0.07]: | OP_AREA_PERCENT ：Based on NVMeVirt's default of 0.07. |
The over-provisioning space for the metadata area and the data area (when using a block interface). It ensures the reserved space is at least 7% of the visible space in the default case. |
Here is the meaning of each output:
| Output | Corresponding ssd_config.h Option after #elif (BASE_SSD == CONZONE_PROTOTYPE) |
Meaning or Influence |
|---|---|---|
| [Zone Size] | ZONE_SIZE : Usually doesn't need to be changed; it is BLK_SIZE * DIES_PER_ZONE. |
The size of a zone. |
| [Super Block Size] | None. | The superblock size is usually the same as the Zone Size. |
| [pSLC Flash Block Size] | None. | The size of a "Regular" flash block when used for SLC. |
| [pSLC Flash Block Capacity] | None. | The actual usable space after programming a "Regular" flash block as SLC. |
| [Physical Data Size] | None. | 用The user-visible space plus the space occupied by "Regular" flash blocks used for SLC. |
| [Physical Meta Size] | PHYSICAL_META_SIZE |
Ensures block alignment and OP requirements are met. It's the size of the "Regular" flash blocks occupied by the meta namespace (since the meta namespace uses SLC, the actual usable physical space is also reduced). |
| Insmod Command | The command for launching. | |
| [WARN] physical_data_size should be 4104M | A warning that the actual user-visible physical space might differ due to block size alignment. |
If you modify ssd_config.h, you must recompile:
make -j `nproc`
ssd_config.h has an SLC_BYPASS variable, which lets you choose whether to bypass the SLC buffer.
-
TLC: Usually set
SLC_BYPASSto 1 (bypass). -
QLC: Must set
SLC_BYPASSto 0 (do not bypass).
Then, run the provided command.
# With all default values
sudo insmod ./nvmev.ko memmap_start=82G memmap_size=8833M cpus=7,8If 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 I have added some startup output information that you can view with sudo dmesg, for example:
[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 createdConZone's code includes modified mkfs.tool source to help you determine the logical size of namespace 0.
If you are unsure how much space to allocate for metadata, you can first assume it is twice the size of your zone. Then, run the following command with sudo:
sudo ./f2fs-tools-1.14.0/build/sbin/mkfs.f2fs -f -m -c /dev/nvme2n2 /dev/nvme2n1P.S. The -m parameter is not needed for formatting a block interface SSD.
The output will look something like this:
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 65536You can see that “main blkaddr” and the starting position of “device 1“ are the same, which means it was successful.
If the size you set is too large, reduce LOGICAL_META_SIZE by one zone. If it's too small, increase it by one zone. Keep adjusting until it is correct.
Note: After adjusting, you must rerun scripts/size.py, check if other parameters have changed, recompile, run with the generated command, and then reformat with the tool.
Mount the meta namespace disk.
# mnt is my custom mount directory
sudo mount /dev/nvme2n1 mntNow, you can test its performance using tools like FIO, Mobibench, or others, just like any regular disk.
For batch testing, I've created the exp.py script (for a complete batch test), mount.py and umount.py scripts (for individual mount/unmount operations, useful for single tests) in the scripts/ directory. Remember to modify WORK_DIR and INSMOD_CMD in these scripts.
(P.S. I have also included the Mobibench source code in the repository, which may be helpful!)
sudo umount mnt
sudo rmmod nvmevI have added some potentially useful statistics that you can view with sudo dmesg, for example:
[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.)