Local Storage

Each Voltage Park On Demand bare metal server has a 512GB boot disk and 6 3.2TB NVMe SSDs of locally-attached storage. This article will guide you on how to mount a partition.

Overview

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By default, Voltage Park On Demand bare metal servers come with 1 NVMe SSD mounted at the root partition. Additional NVMe SSDs come unmounted, providing unparalleled customizability for HPC workloads — you can configure custom hyperconverged storage clusters, distributed storage, and RAID.

In this article, we'll guide you on how to create an LVM volume from the 6 disks not mounted at the / partition and mount it at /data.

Step 1: Status Check

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1. When deploying your server, verify that all disks are present by running the following command:

 sudo fdisk -l

1. Confirm that disks /dev/nvme1n1 through /dev/nvme6n1 are present.

ubuntu@gXXX:~$ sudo fdisk -l

Disk /dev/nvme1n1: 2.91 TiB, 3200631791616 bytes, 6251233968 sectors
Disk model: Dell Ent NVMe PM1735a MU 3.2TB          
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

# Confirm that /dev/nvme1n1 through /dev/nvme6n1 are present

Step 2: Set up the LVM partition

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1. Initialize the physical volume across all NVMe SSDs

Run the following command:

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

Confirm that your output matches the following:

ubuntu@gXXX:~$ sudo pvcreate /dev/nvme1n1 /dev/nvme2n1 /dev/nvme3n1 /dev/nvme4n1 /dev/nvme5n1 /dev/nvme6n1

  Physical volume "/dev/nvme1n1" successfully created.
  Physical volume "/dev/nvme2n1" successfully created.
  Physical volume "/dev/nvme3n1" successfully created.
  Physical volume "/dev/nvme4n1" successfully created.
  Physical volume "/dev/nvme5n1" successfully created.
  Physical volume "/dev/nvme6n1" successfully created.

1. Initialize a volume group across all NVMe SSDs

Run the following command:

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

Confirm that your output matches the following:

ubuntu@gXXX:~$ sudo vgcreate nvme_vg /dev/nvme1n1 /dev/nvme2n1 /dev/nvme3n1 /dev/nvme4n1 /dev/nvme5n1 /dev/nvme6n1
  Volume group "nvme_vg" successfully created

1. Create an LVM spanning the volume group

Run the following command:

sudo lvcreate -l 100%FREE -n nvme_lv nvme_vg

Confirm that your output matches the following:

ubuntu@gXXX:~$ sudo lvcreate -l 100%FREE -n nvme_lv nvme_vg
  Logical volume "nvme_lv" created.

1. Create an ext4 partition spanning this LVM

Run the following command:

sudo mkfs.ext4 /dev/nvme_vg/nvme_lv

Please note that this may take a few moments to complete.

Once completed, confirm that your output looks like the following:

ubuntu@gXXX:~$ sudo mkfs.ext4 /dev/nvme_vg/nvme_lv
mke2fs 1.46.5 (30-Dec-2021)
Discarding device blocks:   132538done

Step 3: Temporarily Mount the LVM to the Filesystem

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1. Create the folder that the LVM will mount to

For this example, we will mount the 6x 3.2 TB LVM at /data. To do this, run the following command:

sudo mkdir /data

If this command succeeds, you will not see any errors returned.

1. Mount the LVM to the folder

Run the following command, replacing /data with the folder where you want to mount the LVM:

sudo mount /dev/nvme_vg/nvme_lv /data

1. Confirm that there are no issues

If you run df -h, you should see the LVM mounted at /data. Please refer to the last line of the output below.

ubuntu@gXXX:~$ df -h
Filesystem                   Size  Used Avail Use% Mounted on
tmpfs                        101G  3.8M  101G   1% /run
/dev/nvme0n1p2               439G   13G  405G   3% /
tmpfs                        504G     0  504G   0% /dev/shm
tmpfs                        5.0M     0  5.0M   0% /run/lock
/dev/nvme0n1p1               511M  6.1M  505M   2% /boot/efi
tmpfs                        101G  4.0K  101G   1% /run/user/1000
/dev/mapper/nvme_vg-nvme_lv   18T   24K   17T   1% /data

If this succeeds, we know that the partition is correctly configured and that our mount point has been correctly created. In Step 4 below, we'll unmount the LVM and configure the partition to be set up on boot.

1. Unmount the LVM

Run the following command:

sudo umount /data

Please make sure that no errors persist beyond this point before proceeding.

Step 4: Permanently Mount the LVM to the Filesystem

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1. Locate the ID of the LVM

Run the following command to find the UUID of the LVM and copy the UUID from the output:

sudo blkid /dev/nvme_vg/nvme_lv

In the following example, the UUID is 505cf49d-a247-428e-8941-6bcf3b72d5b3.

ubuntu@gXXX:~$ sudo blkid /dev/nvme_vg/nvme_lv
/dev/nvme_vg/nvme_lv: UUID="505cf49d-a247-428e-8941-6bcf3b72d5b3" BLOCK_SIZE="4096" TYPE="ext4"

1. Add the UUID to the /etc/fstab

The fstab file defines directories and mount points for the next boot.

• Step 1: Run the following command

sudo nano /etc/fstab

• Step 2: Append the following line to the bottom of the file, replacing [INSERT UUID HERE] with the UUID you copied from above. UUID=[INSERT UUID HERE] /data ext4 defaults 0 0

Please see the example file below.

# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
# / was on /dev/nvme0n1p2 during curtin installation
/dev/disk/by-uuid/68283bfd-f90f-4904-b753-fd8e7ba41eec / ext4 defaults 0 1
# /boot/efi was on /dev/nvme0n1p1 during curtin installation
/dev/disk/by-uuid/DCE3-DE76 /boot/efi vfat defaults 0 1
/swap.img       none    swap    sw      0       0

UUID=505cf49d-a247-428e-8941-6bcf3b72d5b3 /data ext4 defaults 0 0

To close and exit Nano, press Ctrl + X, then type y when prompted to save changes, and press Enter to confirm.

1. Verify the validity of your /etc/fstab file

The fstab file determines which partitions are mounted at boot.

If this file is invalid and the system reboots, it may fail to boot properly. Therefore, it’s essential to verify that the fstab file is correct and valid.

Run the following command:

sudo findmnt --verify

Make sure your output matches the following:

ubuntu@gXXX:~$ sudo findmnt --verify
none
   [W] non-bind mount source /swap.img is a directory or regular file

0 parse errors, 0 errors, 1 warning

1. Remount your partition

Run the following command:

sudo mount -a

Step 5: Congratulations!

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1. Verify that df -h now shows an 18 TB partition mounted at /data

Run the following command:

df -h

Please review the last line of the output below to confirm that it shows an 18 TB partition mounted at /data.

ubuntu@gXXX:~$ df -h
Filesystem                   Size  Used Avail Use% Mounted on
tmpfs                        101G  3.8M  101G   1% /run
/dev/nvme0n1p2               439G   13G  405G   3% /
tmpfs                        504G     0  504G   0% /dev/shm
tmpfs                        5.0M     0  5.0M   0% /run/lock
/dev/nvme0n1p1               511M  6.1M  505M   2% /boot/efi
tmpfs                        101G  4.0K  101G   1% /run/user/1000
/dev/mapper/nvme_vg-nvme_lv   18T   24K   17T   1% /data

If you've reached this point, congratulations! You're now ready to use your 18TB partition! :)

If you have not yet reached this point and need assistance, please reach out to [e-mail]. Our round-the-clock support is ready to help!