Local Storage (Configuring an LVM Volume on Voltage Park On-Demand Bare Metal Servers)

This guide explains how to configure an LVM volume from six unmounted NVMe SSDs and mount it at /localnvme.

By default, Voltage Park On-Demand bare metal servers have one NVMe SSD mounted at the root partition. Additional NVMe SSDs are unmounted, offering high flexibility for custom HPC workloads.

Step 1: Update and Install LVM2

Before proceeding, ensure that your system is updated and that the LVM2 package is installed.


sudo apt update

sudo apt install -y lvm2

Verify that LVM2 is installed correctly by checking for the pvcreate command:


which pvcreate

Step 2: Check Available Disks

After deploying your server, verify the presence of all disks:


sudo fdisk -l

Ensure that the following disks are available:

/dev/nvme1n1
/dev/nvme2n1
/dev/nvme3n1
/dev/nvme4n1
/dev/nvme5n1
/dev/nvme6n1

Alternatively, list all block devices:


lsblk

Step 3: Initialize Physical Volumes

Create physical volumes for all six unmounted NVMe SSDs:


sudo pvcreate /dev/nvme1n1 /dev/nvme2n1 /dev/nvme3n1 /dev/nvme4n1 /dev/nvme5n1 /dev/nvme6n1

Verify the setup:


sudo pvs

Step 4: Create a Volume Group

Create a volume group named nvme_vg using all six physical volumes:


sudo vgcreate nvme_vg /dev/nvme1n1 /dev/nvme2n1 /dev/nvme3n1 /dev/nvme4n1 /dev/nvme5n1 /dev/nvme6n1

Verify the volume group:


sudo vgs

Step 5: Create a Logical Volume

Create a logical volume named nvme_lv spanning the entire volume group:


sudo lvcreate -l 100%FREE -n nvme_lv nvme_vg

Verify the logical volume:


sudo lvs

Step 6: Format the Logical Volume

Format the logical volume with the ext4 filesystem:


sudo mkfs.ext4 /dev/nvme_vg/nvme_lv

Step 7: Temporarily Mount the Logical Volume

Create the mount point directory:


sudo mkdir -p /localnvme

Mount the logical volume:


sudo mount /dev/nvme_vg/nvme_lv /localnvme

Verify the mount:


df -h

Ensure that /dev/mapper/nvme_vg-nvme_lv is listed as mounted at /localnvme.

Step 8: Create a Symbolic Link

Create a symbolic link to /home/ubuntu/localnvme:


sudo ln -s /localnvme /home/ubuntu/localnvme

Verify the symbolic link:


ls -l /home/ubuntu/localnvme

Step 9: Configure Persistent Mounting

Find the UUID of the logical volume:


sudo blkid /dev/nvme_vg/nvme_lv

Copy the UUID from the output and add it to /etc/fstab:


sudo nano /etc/fstab

Append the following line at the bottom, replacing [INSERT UUID HERE] with the actual UUID:


UUID=[INSERT UUID HERE] /localnvme ext4 defaults 0 0

Save and exit (Ctrl + X, then Y, then Enter).

Verify the fstab file:


sudo findmnt --verify

Ensure there are 0 errors before proceeding.

Step 10: Remount and Validate

Remount all partitions:


sudo mount -a

Verify that the logical volume is correctly mounted:


df -h

Confirm that /dev/mapper/nvme_vg-nvme_lv is mounted at /localnvme with the expected size.

List contents of both directories to validate:


ls /localnvme

ls /home/ubuntu/localnvme

Step 11: Reboot (Optional)

Reboot to ensure the configuration persists across system restarts:


sudo reboot

After rebooting, verify that /localnvme is mounted correctly:


df -h

Experimental Automated setup script


#!/bin/bash

# Color codes

RED='\e[31m'

GREEN='\e[32m'

YELLOW='\e[33m'

BLUE='\e[34m'

CYAN='\e[36m'

RESET='\e[0m'

############################################################

# This script:

# 1) Lists unmounted NVMe disks.

# 2) Creates an LVM volume from selected disks.

# 3) Mounts the new LVM volume at a user-provided mount point.

# 4) Offers the option to create a symbolic link in a chosen user's home directory.

# 5) Explains symbolic links and any necessary permission fixes.

############################################################

############################################################

# Disk Discovery

############################################################

# This function finds only those NVMe disks whose partitions are not mounted.

list_disks() {

echo -e "\n${CYAN}Scanning for unmounted NVMe disks...${RESET}"

available_disks=()

all_nvme_disks=( $(lsblk -dno NAME -e7 | grep nvme) )

for disk in "${all_nvme_disks[@]}"; do

part_mounts=( $(lsblk -rno NAME,TYPE,MOUNTPOINT "/dev/$disk" | awk '$2=="part" && $3!="" {print $3}') )

if [ ${#part_mounts[@]} -eq 0 ]; then

available_disks+=("/dev/$disk")

fi

done

if [ ${#available_disks[@]} -eq 0 ]; then

echo -e "${RED}No unmounted NVMe disks found. Exiting.${RESET}"

exit 1

fi

echo -e "\n${GREEN}Available unmounted NVMe disks:${RESET}"

for i in "${!available_disks[@]}"; do

echo -e "${YELLOW}$((i+1))) ${available_disks[$i]}${RESET}"

done

}

validate_disks() {

for disk in "${selected_disks[@]}"; do

if mount | grep -q "^$disk"; then

echo -e "${RED}Error: $disk is already mounted. Please select unmounted disks.${RESET}"

exit 1

fi

done

}

get_user_choices() {

read -p "Enter the number of disks to use for LVM (default: all found): " disk_count

disk_count=${disk_count:-${#available_disks[@]}}

selected_disks=("${available_disks[@]:0:$disk_count}")

validate_disks

echo -e "\n${BLUE}Selected disks: ${selected_disks[@]}${RESET}"

read -p "Enter mount point (default: /localnvme): " mount_path

mount_path=${mount_path:-/localnvme}

}

############################################################

# LVM Setup and Mounting

############################################################

setup_lvm() {

echo -e "\n${CYAN}Setting up LVM...${RESET}"

sudo apt update && sudo apt install -y lvm2

echo -e "\n${GREEN}Initializing physical volumes...${RESET}"

for disk in "${selected_disks[@]}"; do

if sudo pvs | grep -q "$disk"; then

echo -e "${YELLOW}Warning: $disk is already part of a volume group. Skipping pvcreate.${RESET}"

else

if ! sudo pvcreate "$disk"; then

echo -e "${RED}Error: Failed to initialize physical volume on $disk. Exiting.${RESET}"

exit 1

fi

fi

done

echo -e "\n${GREEN}Creating volume group (nvme_vg)...${RESET}"

if ! sudo vgcreate nvme_vg "${selected_disks[@]}"; then

echo -e "${RED}Error: Failed to create volume group. Exiting.${RESET}"

exit 1

fi

echo -e "\n${GREEN}Creating logical volume (nvme_lv)...${RESET}"

if ! sudo lvcreate -l 100%FREE -n nvme_lv nvme_vg; then

echo -e "${RED}Error: Failed to create logical volume. Exiting.${RESET}"

exit 1

fi

echo -e "\n${GREEN}Formatting logical volume...${RESET}"

sudo mkfs.ext4 /dev/nvme_vg/nvme_lv

}

mount_lvm() {

echo -e "\n${CYAN}Creating mount point at $mount_path...${RESET}"

sudo mkdir -p "$mount_path"

echo -e "\n${GREEN}Mounting LVM volume...${RESET}"

if ! sudo mount /dev/nvme_vg/nvme_lv "$mount_path"; then

echo -e "${RED}Error: Failed to mount LVM volume. Exiting.${RESET}"

exit 1

fi

}

persist_mount() {

echo -e "\n${CYAN}Persisting mount configuration...${RESET}"

uuid=$(sudo blkid -s UUID -o value /dev/nvme_vg/nvme_lv)

if [ -z "$uuid" ]; then

echo -e "${RED}Error: Could not retrieve UUID. Exiting.${RESET}"

exit 1

fi

echo "UUID=$uuid $mount_path ext4 defaults 0 0" | sudo tee -a /etc/fstab

echo -e "\n${GREEN}Verifying fstab...${RESET}"

sudo findmnt --verify

}

############################################################

# Symbolic Link Setup

############################################################

setup_symbolic_link() {

echo -e "\n${CYAN}Would you like to create a symbolic link to your mount point? [y/N]${RESET}"

read -p "Enter 'y' or 'n': " symlink_choice

# Convert symlink_choice to lowercase

symlink_choice="${symlink_choice,,}"

if [[ "$symlink_choice" == "y" ]]; then

echo -e "\n${CYAN}Listing system users (excluding root):${RESET}"

users=( $(awk -F: '{ if($1 != "root") print $1}' /etc/passwd) )

for i in "${!users[@]}"; do

echo -e "${YELLOW}$((i+1))) ${users[$i]}${RESET}"

done

read -p "Select a user for the symbolic link: " user_choice

if [[ "$user_choice" =~ ^[0-9]+$ ]] && [ "$user_choice" -ge 1 ] && [ "$user_choice" -le ${#users[@]} ]; then

selected_user="${users[$((user_choice-1))]}"

else

echo -e "${RED}Invalid user selection. Skipping symbolic link creation.${RESET}"

return

fi



user_home="/home/$selected_user"

if [ ! -d "$user_home" ]; then

echo -e "${RED}Home directory for user $selected_user not found. Skipping symbolic link creation.${RESET}"

return

fi



local link_path="$user_home/localnvme"

echo -e "\n${BLUE}Creating symbolic link at $link_path...${RESET}"

sudo ln -s "$mount_path" "$link_path"

echo -e "\n${YELLOW}Note: A symbolic link (symlink) is a shortcut that points to another location."

echo -e "If $selected_user does not have permission to access $mount_path, run:${RESET}"

echo -e "${CYAN}sudo chown -R $selected_user:$selected_user $mount_path${RESET}"

echo -e "\n${YELLOW}This command changes ownership of $mount_path to $selected_user so they can read/write in that directory if needed.${RESET}"

else

echo -e "${BLUE}Skipping symbolic link creation.${RESET}"

fi

}



############################################################

# Main Menu

############################################################

main_menu() {

while true; do

echo -e "\n${YELLOW}VoltagePark LVM Creator${RESET}"

echo -e "${CYAN}1) List available unmounted NVMe disks${RESET}"

echo -e "${CYAN}2) Configure LVM and mount${RESET}"

echo -e "${CYAN}3) Exit${RESET}"

read -p "Select an option: " choice

case $choice in

1)

list_disks

;;

2)

list_disks

get_user_choices

setup_lvm

mount_lvm

persist_mount

setup_symbolic_link

echo -e "\n${GREEN}Setup complete!${RESET}"

;;

3)

exit 0

;;

*)

echo -e "${RED}Invalid option. Try again.${RESET}"

;;

esac

done

}



# Start the script

main_menu

```

Conclusion

Congratulations! You have successfully created an LVM volume using six unmounted NVMe SSDs and permanently mounted it at /localnvme. You can now use this storage for high-performance workloads.

If you encounter issues, reach out to support@voltagepark.com for assistance.