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Latchu@DevOps
Latchu@DevOps

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Part-33: ⚡Configuring VM with Local SSD in Google Cloud Platform (GCP)

#googlecloud #virtualmachine #cloud #tutorial

When deploying compute workloads in Google Cloud, you generally choose between Persistent Disks (PDs) and Local SSDs.

  • Persistent Disks: Durable, network-attached, can be resized, backed up with snapshots, and survive VM reboots.
  • Local SSDs: Physically attached to the host, extremely fast (high IOPS & throughput), but ephemeral – data does not persist if the VM is deleted (unless explicitly preserved during stop).

In this tutorial, we’ll walk through how to:

  1. Create a VM with a Local SSD
  2. Format and mount the SSD
  3. Configure auto-mount after reboot
  4. Test persistence across reboots and stops
  5. Clean up resources

🔹 Step 1: Create VM with Local SSD

👉 From the Console:

  • Go to Compute Engine → VM Instances → Create Instance
  • Name: demo9-vm-localssd
  • Region: us-central1
  • Zone: us-central1-a
  • Machine family: N2 (not all series support Local SSDs)
  • Machine type: n2-standard-2
  • Boot Disk: Debian 9 (check OS compatibility for Local SSDs)
  • Under Advanced Options → Disks → Add Local SSD
  • Click Create

👉 Equivalent CLI command:

gcloud compute instances create demo9-vm-localssd \
    --project=gcpdemos \
    --zone=us-central1-a \
    --machine-type=n2-standard-2 \
    --network-interface=subnet=default \
    --tags=http-server \
    --local-ssd=interface=NVME
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🔹 Step 2: Format & Mount the SSD

Connect to the VM:

gcloud compute ssh --zone "us-central1-a" "demo9-vm-localssd" --project "gcpdemos"
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Check block devices:

sudo lsblk
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Format the Local SSD with ext4:

sudo mkfs.ext4 -F /dev/nvme0n1
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Create a mount directory and mount the disk:

sudo mkdir -p /mnt/disks/disk1ssd
sudo mount /dev/nvme0n1 /mnt/disks/disk1ssd
sudo chmod a+w /mnt/disks/disk1ssd
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Verify:

sudo df -h
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✅ You should see /dev/nvme0n1 mounted at /mnt/disks/disk1ssd.

🔹 Step 3: Auto-Mount SSD on Reboot

Local SSDs won’t automatically mount after reboot unless configured.

Backup fstab:

sudo cp /etc/fstab /etc/fstab_backup_before_localssd
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Get the UUID:

sudo blkid -s UUID
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Add entry to /etc/fstab:

echo UUID=<YOUR-UUID-HERE> /mnt/disks/disk1ssd ext4 discard,defaults,nofail 0 2 | sudo tee -a /etc/fstab
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Verify:

cat /etc/fstab
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🔹 Step 4: Test the SSD

Write a test file:

sudo echo "Welcome to GCP Local SSD - Host: $(hostname)" | sudo tee /mnt/disks/disk1ssd/localssd.html
cat /mnt/disks/disk1ssd/localssd.html
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Reboot the VM:

sudo reboot
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Reconnect and verify:

df -h
ls -lrt /mnt/disks/disk1ssd/
cat /mnt/disks/disk1ssd/localssd.html
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✅ The SSD remounts automatically, and your file persists across reboots.

🔹 Step 5: Important Notes on Local SSDs

  1. If you stop the VM, you must decide whether to preserve or discard SSD data.
  2. Flags to remember:
  • --discard-local-ssd=True → discard data
  • --discard-local-ssd=False → preserve data (at cost)

Example:

# Stop VM & preserve SSD
gcloud compute instances stop demo9-vm-localssd --zone=us-central1-a --discard-local-ssd=False
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🔹 Step 6: Cleanup 

# Stop VM
gcloud compute instances stop demo9-vm-localssd --zone=us-central1-a

# Delete VM
gcloud compute instances delete demo9-vm-localssd --zone=us-central1-a
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✅ Wrap Up

  • Persistent Disks are durable and snapshot-friendly.
  • Local SSDs give blazing-fast performance but require careful handling since they are ephemeral by default.
  • Best suited for high-performance workloads like caching, databases with replication, or temporary storage needs.

🚀 Now you can confidently create and manage VMs with Local SSDs in GCP.

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