# libnvmf

**Repository Path**: cdevel/libnvmf

## Basic Information

- **Project Name**: libnvmf
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: GPL-2.0
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2026-03-02
- **Last Updated**: 2026-03-10

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# libnvmf - High Performance NVMe-oF Library

A lightweight, high-performance NVMe-oF (TCP/RDMA) library for Linux.

## Key Features

- **Protocol Support**: NVMe-oF TCP and RDMA.
- **High Performance**: 
  - **Smart Kick**: Reduces syscall overhead by >80%.
  - **Natural Batching**: Auto-tuning IO batching for low latency and high throughput.
  - **Polling Mode**: User-space busy polling (`-P`) for ultra-low latency.
  - **SQPOLL**: Kernel submission offload (`-O`).
- **Multipath**: High availability with Failover and Load Balancing.
- **Asynchronous API**: Based on `io_uring` (TCP) and `libibverbs` (RDMA).

## Build library
```
cd lib
make
```

or enable RDMA(need rdmacm/ibverbs development package. Ex, installing on Debian/Ubuntu by command: apt-get install librdmacm-dev libibverbs-dev):
```
make USE_RDMA=1
```

or enable debug(flood of log):
```
make DEBUG=1
```

or enable memory leak test:
```
make MALLOC_DEBUG=1 USE_RDMA
MALLOC_TRACE=/dev/shm ./nvmf-fio --filename=rdma://192.168.122.33:4420/nvmet-always/1 --randrw --iodepth=32 --ioqueues=4 --runtime=3

../scripts/checkleak.py /dev/shm/nvmf_mtrace_53826
```

## Test
### Run a target
```
modprobe nvmet-tcp

# create a target
mkdir -p /sys/kernel/config/nvmet/subsystems/nvmet-always-tcp
echo 1 > /sys/kernel/config/nvmet/subsystems/nvmet-always-tcp/attr_allow_any_host
echo 0123456789abcdef > /sys/kernel/config/nvmet/subsystems/nvmet-always-tcp/attr_serial

sleep 0.1
mkdir -p /sys/kernel/config/nvmet/subsystems/nvmet-always-tcp/namespaces/1
# select your image path
echo "/nvme/nvme.img" > /sys/kernel/config/nvmet/subsystems/nvmet-always-tcp/namespaces/1/device_path
echo 1 > /sys/kernel/config/nvmet/subsystems/nvmet-always-tcp/namespaces/1/enable

sleep 0.1
mkdir -p /sys/kernel/config/nvmet/ports/2
echo ipv4 > /sys/kernel/config/nvmet/ports/2/addr_adrfam
echo "192.168.122.33" > /sys/kernel/config/nvmet/ports/2/addr_traddr
echo 4420 > /sys/kernel/config/nvmet/ports/2/addr_trsvcid
echo tcp > /sys/kernel/config/nvmet/ports/2/addr_trtype
ln -s /sys/kernel/config/nvmet/subsystems/nvmet-always-tcp/ /sys/kernel/config/nvmet/ports/2/subsystems/nvmet-always-tcp

```

### Run nvmf-fio example
```
cd examples
make fio

./nvmf-fio --filename=nvmf-tcp://192.168.122.33:4420/nvmet-always-tcp/1 --randrw --iodepth=32 --ioqueues=4 --runtime=100

Or run rdma:
./nvmf-fio --filename=nvmf-rdma://192.168.122.33:4420/nvmet-always-rdma/1 --randrw --iodepth=32 --ioqueues=4 --runtime=100
```

### Test reconnect TCP
On target side:
```
iptables -A INPUT -p tcp --dport 4420 -j DROP; sleep 6; dmesg -T -c; iptables -F
```

### Test reconnect RDMA
On target side (RXE case):
```
iptables -A INPUT -p udp --dport 4791 -j DROP; sleep 6; dmesg -T -c; iptables -F
```