How to find SAN LUN Mapped to VxVM Disk in Linux

Summary: This article provides an efficient shell script to find LUN IDs associated with VxVM (Veritas Volume Manager) disks in Linux environments. Understanding LUN mapping is crucial for managing storage resources effectively, especially in VCS clusters. This guide includes a step-by-step breakdown of the script’s functionality, ensuring you can easily implement it to streamline your data storage management.

Mapping LUN IDs to VxVM Disks in Linux

In managing storage within a VCS cluster, knowing how to map LUN IDs to VxVM (Veritas Volume Manager) disks is essential, especially when expanding your VxFS file system. This guide will explore how to efficiently locate LUN numbers linked to VxVM disks in your Linux setup.

Shell Script for LUN Mapping

This shell script is designed to help you identify which storage LUN is associated with each VxVM disk on your Linux system.

How the Script Works

The script follows these steps to gather and present the necessary information:

• Collects a list of active Disk Groups (DG) in your system.
• Identifies the Device Names linked to these Disk Groups.
• Lists the Block Devices mapped with the respective devices.
• Retrieves the associated LUN IDs for these block devices and displays them alongside the DG names.

vi VxVM_disk_mapping_with_LUN_number.sh

#!/bin/bash
###########################################################
# Purpose: Mapping LUN Number to VxVM Disk in Linux
# Author: 2DayGeek
# Version: v1.0
###########################################################

echo "DG_Name       Block_Device        LUN_Number"
echo "-------------------------------------------------------------------"
for dg_name in `vxdg list | awk '{print $1}' | grep -v NAME`
do
    for d_name in `vxdisk -e list | grep -i $dg_name | awk '{print $1}'`
    do 
        for b_device in `vxdisk list $d_name | grep -w state=enabled | awk '{print $1}' | head -1`
        do
            echo "$dg_name --> $b_device --> $(lsscsi --scsi | grep $b_device | awk '{print $NF}')"
        done
    done
done | column -t

Make sure to set executable permissions for the shell script:

chmod +x VxVM_disk_mapping_with_LUN_number.sh

Execute the script to view your results:

sh VxVM_disk_mapping_with_LUN_number.sh

The output will display the DG name, Block devices, and their associated LUNs, similar to the example shown below:

On-the-Fly One-Liner Script

If you prefer a quick one-liner to run on the fly, use the following command:

# for dg_name in `vxdg list | awk '{print $1}' | grep -v NAME`; do for d_name in `vxdisk -e list | grep -i $dg_name | awk '{print $1}`; do for b_device in `vxdisk list $d_name | grep -w state=enabled | awk '{print $1}' | head -1`; do echo "$dg_name --> $b_device --> $(lsscsi --scsi | grep $b_device | awk '{print $NF}')"; done; done; done | column -t

Conclusion

This tutorial provided a comprehensive look at how to find the LUN number associated with a VxVM (Veritas Volume Manager) disk in Linux. With this script, managing your storage resources becomes much more simplified.

Frequently Asked Questions (FAQ)

1. What is a LUN ID, and why is it important?

A LUN ID (Logical Unit Number) is a unique identifier used to designate a logical unit of storage. It is essential for effectively managing disk resources in storage area networks (SAN) or similar configurations.

2. Can I modify the script for additional functionality?

Yes, the script can be customized according to your needs, such as adding filters for specific storage devices or logging the output to a file for future reference.

3. Is it necessary to understand VxVM to use this script?

While some knowledge of Veritas Volume Manager (VxVM) and Linux command-line operations is beneficial, the script is designed to be user-friendly for those familiar with basic Linux commands.