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Configure Virtual Data Optimizer (VDO) in CentOS 8

Alaric Bird
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Learn how to configure Virtual Data Optimizer (VDO) in CentOS 8 to optimize storage with deduplication, compression, and thin provisioning for efficient disk space management. #centlinux #linux #storage

What is Virtual Data Optimizer?

VDO (Virtual Data Optimizer) is a storage software that can be used as an additional storage layer under the local filesystems, iSCSI or Ceph storages. VDO provides inline data reduction for Linux in the form of deduplication, compression and thin provisioning.

VDO is commonly used in enterprise environments to maximize the use of existing storage infrastructure, improve performance, and reduce costs. It is especially beneficial in virtualized environments, where data redundancy and storage sprawl can become significant issues.

In this article, we will configure Virtual Data Optimizer (VDO) on CentOS 8 and then we will create filesystem and persistently mount the volume.

Configure Virtual Data Optimizer (VDO) in CentOS 8

Virtual Data Optimizer (VDO) Features

The core features of Virtual Data Optimizer (VDO) are:

Virtual Data Optimizer (VDO) Applications

Although we can use Virtual Data Optimizer (VDO) in various situations to save disk space, but two major applications of VDO are:

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Linux Server Specification

We have provisioned a virtual machine with a minimal installation of CentOS 8, ensuring a lightweight and efficient setup. This minimal installation provides a base operating system with only essential packages, reducing resource usage and potential security vulnerabilities.

The virtual machine is configured with the following hardware specifications, which are optimized for stability and performance in our environment:

This minimal installation setup provides a clean and controlled environment, allowing us to configure Virtual Data Optimizer (VDO) efficiently while maintaining a lightweight footprint on system resources.

Install Virtual Data Optimizer (VDO) on CentOS 8

To begin the configuration process, we need to connect to the CentOS 8 server where Virtual Data Optimizer (VDO) will be set up.

Use an SSH client to connect to the server named vdo-storage-01.centlinux.com as the root user. This ensures we have the necessary administrative privileges to install and configure Virtual Data Optimizer.

Before proceeding with the installation, it is essential to refresh the DNF package manager cache. This step ensures that we have access to the latest package versions and necessary dependencies for a smooth installation process.

# dnf makecache
CentOS-8 - AppStream                            3.0 kB/s | 4.3 kB     00:01
CentOS-8 - Base                                 2.8 kB/s | 3.9 kB     00:01
CentOS-8 - Extras                               730  B/s | 1.5 kB     00:02
Metadata cache created.

To ensure system stability, security, and compatibility with the latest software packages, it is important to update all installed packages on CentOS 8 before proceeding with any further configurations.

By updating the system, we can:

Use the following command to update all installed packages and refresh the system repositories. This step will ensure that the latest bug fixes, kernel updates, and software enhancements are applied to the server.

# dnf update -y

To setup Virtual Data Optimizer on CentOS 8, we have to install following two packages.

We are installing both of these packages using a single dnf command.

# dnf install -y kmod-kvdo vdo

The Virtual Data Optimizer (VDO) service is automatically enabled and started by the installer.

# systemctl status vdo.service
â vdo.service - VDO volume services
   Loaded: loaded (/usr/lib/systemd/system/vdo.service; enabled; vendor preset:>
   Active: active (exited) since Sun 2019-12-22 12:54:27 PKT; 20min ago
 Main PID: 801 (code=exited, status=0/SUCCESS)
    Tasks: 0 (limit: 5948)
   Memory: 0B
   CGroup: /system.slice/vdo.service

Dec 22 12:54:12 vdo-storage-01.centlinux.com systemd[1]: Starting VDO volume serv>
Dec 22 12:54:27 vdo-storage-01.centlinux.com systemd[1]: Started VDO volume servi>

Virtual Data Optimizer (VDO) has been installed on CentOS 8.

Read Also: How to configure Stratis Filesystem on CentOS 8

Create a VDO Volume

We have added an additional storage disk to our CentOS 8 virtual machine, which is recognized as /dev/sdb. This extra disk will be utilized as the VDO data store, where we will create VDO volumes for optimized storage management.

By configuring /dev/sdb as the dedicated VDO storage device, we aim to:

However, while attempting to create a VDO volume on /dev/sdb, we encountered the following error message, which may be due to missing dependencies, incorrect configurations, or conflicts with existing storage settings. To resolve this issue, we will analyze the error, troubleshoot the possible causes, and apply the necessary fixes to ensure a successful VDO setup.

# vdo create --name=vdo1 --device=/dev/sdb --vdoLogicalSize=1T
Creating VDO vdo1
vdo: ERROR - Kernel module kvdo not installed
vdo: ERROR - modprobe: FATAL: Module kvdo not found in directory /lib/modules/4.18.0-80.el8.x86_64

It is a known bug and as a workaround, we restarted the CentOS 8 server.

# systemctl reboot

After restart, we try to create the VDO volume again, and it is working now.

# vdo create --name=vdo1 --device=/dev/sdb --vdoLogicalSize=1T
Creating VDO vdo1
Starting VDO vdo1
Starting compression on VDO vdo1
VDO instance 0 volume is ready at /dev/mapper/vdo1

Since we are utilizing a VDO (Virtual Data Optimizer) volume as a local filesystem, it is essential to format the volume with a suitable filesystem before it can be used for data storage and access.

Creating a filesystem on the VDO volume will allow us to:

Depending on the use case, we can choose a filesystem type such as ext4, XFS, or Btrfs, with XFS being the recommended choice for CentOS 8 due to its scalability and performance advantages. Once the filesystem is created, we will also need to mount the VDO volume so it becomes accessible within the system for storing and managing data efficiently.

# mkfs.xfs -K /dev/mapper/vdo1
meta-data=/dev/mapper/vdo1       isize=512    agcount=4, agsize=67108864 blks
         =                       sectsz=4096  attr=2, projid32bit=1
         =                       crc=1        finobt=1, sparse=1, rmapbt=0
         =                       reflink=1
data     =                       bsize=4096   blocks=268435456, imaxpct=5
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0, ftype=1
log      =internal log           bsize=4096   blocks=131072, version=2
         =                       sectsz=4096  sunit=1 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0

Persistently Mount VDO Volume

Create a directory to mount our VDO volume.

# mkdir /mnt/vdo1

To persistently mount our VDO volume, we must add an entry in /etc/fstab file.

# vi /etc/fstab

Add following line in this file.

/dev/mapper/vdo1        /mnt/vdo1       xfs     defaults,x-systemd.req=vdo.service,discard      0 0

Execute following command to inform Systemd about the new entry in /etc/fstab file.

# systemctl daemon-reload

Mount entries in /etc/fstab file.

# mount -a

Check list of block devices.

# lsblk
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda           8:0    0   60G  0 disk
ââsda1        8:1    0    1G  0 part /boot
ââsda2        8:2    0   59G  0 part
  ââcl-root 253:0    0 38.2G  0 lvm  /
  ââcl-swap 253:1    0  2.1G  0 lvm  [SWAP]
  ââcl-home 253:2    0 18.7G  0 lvm  /home
sdb           8:16   0   10G  0 disk
ââvdo1      253:3    0    1T  0 vdo  /mnt/vdo1
sr0          11:0    1  6.7G  0 rom

Check status of VDO volumes.

# vdostats
Device               1K-blocks      Used Available Use% Space saving%
/dev/mapper/vdo1      10485760   4200156   6285604  40%           99%

We have successfully configured VDO on CentOS 8.

Final Thoughts

Configuring Virtual Data Optimizer (VDO) on CentOS 8 can significantly enhance your storage efficiency by reducing the physical footprint of your data through deduplication, compression, and thin provisioning. By implementing VDO, you can optimize your storage resources, improve system performance, and lower overall costs.

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FAQs

1. What is Virtual Data Optimizer (VDO) in CentOS 8?
VDO (Virtual Data Optimizer) is a block-level storage optimization technology that helps reduce storage usage through deduplication, compression, and thin provisioning, improving disk space efficiency.

2. What are the benefits of using VDO on CentOS 8?
VDO helps optimize disk space, reduce storage costs, and improve data efficiency by eliminating duplicate data blocks and compressing stored data, making it ideal for virtualized and cloud environments.

3. What are the system requirements for configuring VDO?
To configure VDO, you need a CentOS 8 system with a dedicated block device or partition, sufficient available disk space, and the necessary VDO utilities installed.

4. How can I check if VDO is working properly?
After configuring VDO, you can use system commands to monitor VDO statistics, check storage savings, and verify that deduplication and compression are effectively reducing disk usage.

5. Can VDO be used with LVM (Logical Volume Manager)?
Yes, VDO can be integrated with LVM to create optimized logical volumes, allowing better storage management, snapshot capabilities, and increased flexibility for enterprise workloads.

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