LightNVM can be interfaced through the nvme cli tool (nvme-cli). It allows you to create, delete, and manage LightNVM targets and devices.
lnvm can easily be installed on Ubuntu by installing the nvme-cli package
sudo apt-get install nvme
If you are not running Ubuntu or wish to compile from source. It is also available at Github (https://github.com/linux-nvme/nvme-cli)
After nvme cli has been installed, its commands can be listed with:
nvme lnvm --help
To list devices and targets Supported devices register with LightNVM upon initialization. To list registered devices:
nvme lnvm list
To list available targets and their version:
nvme list info
A device must first have a media registered when it is first used (pre-4.11)
nvme lnvm init -d $DEVICE
To add a target on top of a device registered with the gennvm media manager:
nvme lnvm create -d $DEVICE -n $TARGET_NAME -t $TARGET_TYPE -b $LUN_BEGIN -e $LUN_END
- $DEVICE: Backend device. lnvm devices to list available devices.
- $TARGET_NAME: Name of the target to be exposed -> /dev/$TARGET_NAME
- $TARGET_TYPE: Target type. Targets need to be compiled individually before they can be instantiated at run-time. For now, rrpc and pblk are the available implementations.
- $LUN_BEGIN: Lower bound of the LUN range allocated to the target.
- $LUN_END: Higher bound of the LUN range allocated to the target.
After successfully registering the target. You may issue reads and writes to /dev/$TARGET_NAME
For example, to allocate LUNs 0 to 63 to a pblk instance using the NVMe device nvme0n1:
nvme lnvm create -d nvme0n1 -n mydevice -t pblk -b 0 -e 63
A target instance are removed again by:
nvme lnvm remove -n targetname