https://drive.google.com/file/d/1T7Q7rHi056zCesyNwc2tnjbA3hmb1yz_/view?usp=sharing

1. Understanding VDO (Virtual Data Optimizer)

Key Concepts

• Block-level deduplication: Identical data blocks stored once (saves space).
• Compression: LZ4 compression reduces block size.
• Thin provisioning: Logical size can be larger than physical disk (e.g., 300GB logical on 10GB disk).
• Use Cases:
  • VM/image repositories (many identical OS files)
  • Backup targets
  • File servers with duplicate data

⚠️ Critical Notes:

• Not for databases (random I/O hurts performance)
• Not for encrypted data (deduplication fails on unique ciphertext)
• Requires RHEL 8+ or CentOS 8+

2. Installing VDO

Prerequisites

# Enable repositories (if needed)
sudo dnf repolist all

# Install VDO packages
sudo dnf install kmod-kvdo vdo -y

# Start and enable service
sudo systemctl start vdo
sudo systemctl enable vdo
sudo systemctl status vdo    # Verify active

💡 Note:

kmod-kvdo = kernel module, vdo = user-space tools.

3. Creating a VDO Volume

Using Raw Disk (No Partition)

# Create VDO on /dev/sdb (10GB physical)
sudo vdo create --name=vdo1 --device=/dev/sdb --vdoLogicalSize=300G

# Verify
lsblk    # Shows /dev/mapper/vdo1 (300G logical)
sudo vdostats --human-readable    # Shows physical vs logical usage

⚠️ Critical Flags:

• -vdoLogicalSize=300G: Logical size (can be 10x physical)
• No partition needed—VDO uses raw disk

If Creation Fails