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LVM: Flexible Storage

LVM provides flexible storage management. Resize volumes. Combine disks. Create snapshots.

Here's the thing: LVM is advanced. You might not need it. But when you do, it's powerful.

What LVM Does​

LVM abstracts physical storage:

  • Physical Volumes (PV) = Physical disks
  • Volume Groups (VG) = Pool of disks
  • Logical Volumes (LV) = Virtual partitions

Think of it like this: Combine disks into a pool. Create virtual volumes from the pool. Resize as needed.

My take: LVM is like virtual storage. Flexible. Powerful. But complex.

Basic LVM​

Create Physical Volume​

sudo pvcreate /dev/sda1
sudo pvcreate /dev/sdb

My take: Physical volumes are disks for LVM. Create them first.

Create Volume Group​

sudo vgcreate myvg /dev/sda1 /dev/sdb

My take: Volume groups pool physical volumes. Combine disks.

Create Logical Volume​

sudo lvcreate -L 10G -n mylv myvg

My take: Logical volumes are virtual partitions. Create from volume group.

Use Logical Volume​

# Format
sudo mkfs.ext4 /dev/myvg/mylv

# Mount
sudo mount /dev/myvg/mylv /mnt/data

My take: Use logical volumes like regular partitions. Format. Mount. Use.

Resizing Volumes​

Extend Logical Volume​

# Extend LV
sudo lvextend -L +5G /dev/myvg/mylv

# Resize filesystem
sudo resize2fs /dev/myvg/mylv

My take: LVM lets you resize without repartitioning. That's the power.

When to Use LVM​

Use LVM when:

  • You need to resize volumes
  • You have multiple disks
  • You need snapshots
  • Storage needs change

Don't use LVM when:

  • Simple setup is enough
  • You don't need flexibility
  • You're learning basics

My take: LVM is powerful. But you might not need it. Use it when you do.

Common Mistakes (I've Made These)​

  1. Too complex for simple needs: LVM adds complexity. Use it when needed.

  2. Not understanding layers: PV → VG → LV. Understand the layers.

  3. Resizing without resizing filesystem: Extend LV, then resize filesystem.

  4. Removing wrong volume: Be careful. Removing volumes loses data.

  5. Not backing up: LVM is complex. Backup before major changes.

Real-World Examples​

Create LVM Setup​

# Create PVs
sudo pvcreate /dev/sda1 /dev/sdb

# Create VG
sudo vgcreate datavg /dev/sda1 /dev/sdb

# Create LV
sudo lvcreate -L 20G -n datalv datavg

# Format and mount
sudo mkfs.ext4 /dev/datavg/datalv
sudo mount /dev/datavg/datalv /data

What's Next?​

Now that you understand LVM, you have flexible storage. Or learn about Disk Quotas to limit usage.

Personal note: LVM seemed complex at first. Then I used it. Now I appreciate it. It's powerful. But you might not need it. Use it when you do.