In this article, you will learn how to configure Virtual Data Optimizer (VDO) in CentOS 8. #centlinux #linux #storage
Table of Contents
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.
Virtual Data Optimizer (VDO) Features
The core features of Virtual Data Optimizer (VDO) are:
- Supports Local and Remote Storages
- Deduplication
- Compression
- Thin Provisioning
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:
- VM storage
- BLOB storage backends
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Linux Server Specification
We have provisioned virtual machine with minimally installed CentOS 8 with following specification.
- CPU – 3.4 Ghz (2 cores)
- Memory – 1 GB
- Storage – 20 GB
- Operating System – CentOS Linux 8.0
- Hostname – vdo-storage-01.centlinux.com
- IP Address – 192.168.116.206 /24
Install Virtual Data Optimizer (VDO) on CentOS 8
Connect with vdo-storage-01.centlinux.com using ssh as root user.
Build dnf cache using following command.
# 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.
Update CentOS 8 packages as follows.
# dnf update -y
To setup Virtual Data Optimizer on CentOS 8, we have to install following two packages.
- kmod-kvdo – Kernel Modules for Virtual Data Optimizer
- vdo – Management tools for Virtual Data Optimizer
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.
Create a VDO Volume
We have added an extra disk as /dev/sdb in our CentOS 8 virtual machine. We will use /dev/sdb as VDO data store and to create VDO volumes.
While we try to create a VDO volume, we encounter following error.
# 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 using VDO volume as local filesystem, therefore, we need to create a filesystem in VDO volume.
# 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.
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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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