# How to play with LoD

## Run LoD with command line config

```
Usage: lod [-h/--help]
[-d/--dry-run] -n/--node c01,c[02-04] --mds c01 --oss c[02-04] --mdtdevs /dev/sda --ostdevs /dev/sdb --mountpoint /mnt/lod  start/stop/initialize
	-d/--dry-run :*dry* run, don't do real job
	-n/--node :, run lod with specified node list, also means the clients
	-T/--mds :MDS
	-O/--oss :OSS
	-I/--index :instance index
	-m/--mdtdevs :mdt device
	-o/--ostdevs :ost device
	-f/--fsname :lustre instance fsname
	-i/--inet :networks interface, e.g. tcp0, o2ib01
	-p/--mountpoint :mountpoint on client
	-h/--help :show usage

for stage_in/stage_out
lod --source=/foo/foo1 --destination /foo2/ stage_in
lod --sourcelist=/foo/foo1_list --source=/foo_dir --destination /foo2/ stage_out
```
For example:

```
# lod --node=vm2,vm3 --mdtdevs=/dev/vdc --ostdevs=/dev/vdb --fsname=fslod --inet=tcp1 --mountpoint=/mnt/lustre start
```
It'll setup LoD instance with following config:

```
MDS: ['vm2', 'vm3']
	  mdt0,mgs: /dev/vdc	---> vm2
	      mdt1: /dev/vdc	---> vm3
OSS: ['vm2', 'vm3']
	      ost0: /dev/vdb	---> vm2
	      ost1: /dev/vdb	---> vm3
Clients:
	vm2	/mnt/lustre
	vm3	/mnt/lustre
Fsname: fslod
Net: tcp1
Mountpoint: /mnt/lustre
```

## SLURM integration
We provide a slurm burstbuffer plugin named burstbuffer/lod to integrate LoD into SLURM

Checkout lod-dev branch of slurm (https://github.com/DDNStorage/slurm/tree/lod-dev) and build

Enable lod burstbuffer plugin in slurm configuration (slurm.conf):

```
BurstBufferType=burst_buffer/lod
```
Install LoD package in slurm manager node.

```
#cat job.sh

#!/bin/bash
LOD setup node=c[01-04] mdtdevs=/dev/sdb ostdevs=/dev/sdc inet=o2ib01 mountpoint=/mnt/lod
LOD stop
srun jobs_run_on_lod
```
Submit job.sh with sbatch:

```
sbatch job.sh
```