Virtual Data Optimize
是一种通过压缩或删除存储设备上的数据来优化存储空间的技术，简称VDO。
最常见的就是
去重
功能，大大节省了硬盘空间。接下来，我们就来实践一下！
专家建议做虚拟机或
容器
时，采用逻辑与物理
10：1
的比率进行配置，即使用1TB物理存储对应10TB的逻辑存储；而做
对象存储
时（例如Ceph）则采用
3：1
的比率进行配置，即使用1TB物理存储对应3TB的逻辑存储。
VDO虚拟数据优化
一 创建VDO卷
1 首先在虚拟机里添加l一块10G硬盘，进过查询硬盘为sdb，这里不做演示。
2 创建VDO卷，卷名xiaofeng 容量100G
vdo create –name=xiaofeng –device=/dev/sdb –vdoLogicalSize=100G
[root@linuxprobe ~]# vdo create --name=xiaofeng --device=/dev/sdb --vdoLogicalSize=100G
Creating VDO xiaofeng
Starting VDO xiaofeng
Starting compression on VDO xiaofeng
VDO instance 0 volume is ready at /dev/mapper/xiaofeng二 查看刚才创建的VDO卷信息 vdo status –name=xiaofeng
[root@linuxprobe ~]# vdo status --name=xiaofeng
VDO status:
Date: '2021-06-30 08:13:53+08:00'
Node: linuxprobe.com
Kernel module:
Loaded: true
Name: kvdo
Version information:
kvdo version: 6.2.0.293
Configuration:
File: /etc/vdoconf.yml
Last modified: '2021-06-30 08:07:51'
VDOs:
xiaofeng:
Acknowledgement threads: 1
Activate: enabled
Bio rotation interval: 64
Bio submission threads: 4
Block map cache size: 128M
Block map period: 16380
Block size: 4096
CPU-work threads: 2
Compression: enabled
Configured write policy: auto
Deduplication: enabled
Device mapper status: 0 209715200 vdo /dev/sdb normal - online online 1049638 2621440
Emulate 512 byte: disabled
Hash zone threads: 1
Index checkpoint frequency: 0
Index memory setting: 0.25
Index parallel factor: 0
Index sparse: disabled
Index status: online
Logical size: 100G
Logical threads: 1
Max discard size: 4K
Physical size: 10G
Physical threads: 1
Slab size: 2G
Storage device: /dev/disk/by-id/ata-VMware_Virtual_SATA_Hard_Drive_01000000000000000001
VDO statistics:
/dev/mapper/xiaofeng:
1K-blocks: 10485760
1K-blocks available: 6287208
1K-blocks used: 4198552
512 byte emulation: false
KVDO module bios used: 37286
KVDO module bytes used: 424949088
KVDO module peak bio count: 37574
KVDO module peak bytes used: 424952976
bios acknowledged discard: 0
bios acknowledged flush: 0
bios acknowledged fua: 0
bios acknowledged partial discard: 0
bios acknowledged partial flush: 0
bios acknowledged partial fua: 0
bios acknowledged partial read: 0
bios acknowledged partial write: 0
bios acknowledged read: 261
bios acknowledged write: 0
bios in discard: 0
bios in flush: 0
bios in fua: 0
bios in partial discard: 0
bios in partial flush: 0
bios in partial fua: 0
bios in partial read: 0
bios in partial write: 0
bios in progress discard: 0
bios in progress flush: 0
bios in progress fua: 0
bios in progress read: 0
bios in progress write: 0
bios in read: 261
bios in write: 0
bios journal completed discard: 0
bios journal completed flush: 0
bios journal completed fua: 0
bios journal completed read: 0
bios journal completed write: 0
bios journal discard: 0
bios journal flush: 0
bios journal fua: 0
bios journal read: 0
bios journal write: 0
bios meta completed discard: 0
bios meta completed flush: 0
bios meta completed fua: 0
bios meta completed read: 4
bios meta completed write: 65
bios meta discard: 0
bios meta flush: 1
bios meta fua: 1
bios meta read: 4
bios meta write: 65
bios out completed discard: 0
bios out completed flush: 0
bios out completed fua: 0
bios out completed read: 0
bios out completed write: 0
bios out discard: 0
bios out flush: 0
bios out fua: 0
bios out read: 0
bios out write: 0
bios page cache completed discard: 0
bios page cache completed flush: 0
bios page cache completed fua: 0
bios page cache completed read: 0
bios page cache completed write: 0
bios page cache discard: 0
bios page cache flush: 0
bios page cache fua: 0
bios page cache read: 0
bios page cache write: 0
block map cache pressure: 0
block map cache size: 134217728
block map clean pages: 0
block map dirty pages: 0
block map discard required: 0
block map failed pages: 0
block map failed reads: 0
block map failed writes: 0
block map fetch required: 0
block map flush count: 0
block map found in cache: 0
block map free pages: 32768
block map incoming pages: 0
block map outgoing pages: 0
block map pages loaded: 0
block map pages saved: 0
block map read count: 0
block map read outgoing: 0
block map reclaimed: 0
block map wait for page: 0
block map write count: 0
block size: 4096
completed recovery count: 0
compressed blocks written: 0
compressed fragments in packer: 0
compressed fragments written: 0
concurrent data matches: 0
concurrent hash collisions: 0
current VDO IO requests in progress: 0
current dedupe queries: 0
data blocks used: 0
dedupe advice stale: 0
dedupe advice timeouts: 0
dedupe advice valid: 0
entries indexed: 0
flush out: 0
instance: 0
invalid advice PBN count: 0
journal blocks batching: 0
journal blocks committed: 0
journal blocks started: 0
journal blocks writing: 0
journal blocks written: 0
journal commits requested count: 0
journal disk full count: 0
journal entries batching: 0
journal entries committed: 0
journal entries started: 0
journal entries writing: 0
journal entries written: 0
logical blocks: 26214400
logical blocks used: 0
maximum VDO IO requests in progress: 59
maximum dedupe queries: 0
no space error count: 0
operating mode: normal
overhead blocks used: 1049638
physical blocks: 2621440
posts found: 0
posts not found: 0
queries found: 0
queries not found: 0
read only error count: 0
read-only recovery count: 0
recovery progress (%): 0
reference blocks written: 0
release version: 133524
saving percent: 0
slab count: 3
slab journal blocked count: 0
slab journal blocks written: 0
slab journal disk full count: 0
slab journal flush count: 0
slab journal tail busy count: 0
slab summary blocks written: 0
slabs opened: 0
slabs reopened: 0
updates found: 0
updates not found: 0
used percent: 40
version: 30
write amplification ratio: 0.0
write policy: sync
输出信息中包含了VDO卷创建的时间、主机名、版本、是否删重（Deduplication）及是否压缩（Compression）等关键指标。
三 格式化VDO卷
1 格式化VDO卷 mkfs.xfs /dev/mapper/xiaofeng
[root@linuxprobe ~]# mkfs.xfs /dev/mapper/xiaofeng
meta-data=/dev/mapper/xiaofeng isize=512 agcount=4, agsize=6553600 blks
= sectsz=4096 attr=2, projid32bit=1
= crc=1 finobt=1, sparse=1, rmapbt=0
= reflink=1
data = bsize=4096 blocks=26214400, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0, ftype=1
log =internal log bsize=4096 blocks=12800, version=2
= sectsz=4096 sunit=1 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=02 刷新内核信息以确保同步 udevadm settle
[root@linuxprobe ~]# udevadm settle四 挂载VDO卷
1 新建一个用于挂载的目录 mkdir -p /root/new_disk/vdo/xiaofeng
[root@linuxprobe ~]# mkdir -p /root/new_disk/vdo/xiaofeng2 挂载VDO卷 mount /dev/mapper/xiaofeng /root/new_disk/vdo/xiaofeng
[root@linuxprobe ~]# mount /dev/mapper/xiaofeng /root/new_disk/vdo/xiaofeng3 查看VOD卷的真实大小 vdostats –human-readable
[root@linuxprobe ~]# vdostats --human-readable
Device Size Used Available Use% Space saving%
/dev/mapper/xiaofeng 10.0G 4.0G 6.0G 40% 99%4 查看VDO卷的逻辑大小 df -hT
[root@linuxprobe ~]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
devtmpfs devtmpfs 3.9G 0 3.9G 0% /dev
tmpfs tmpfs 3.9G 0 3.9G 0% /dev/shm
tmpfs tmpfs 3.9G 9.9M 3.9G 1% /run
tmpfs tmpfs 3.9G 0 3.9G 0% /sys/fs/cgroup
/dev/mapper/rhel-root xfs 44G 4.1G 40G 10% /
/dev/sda1 xfs 1014M 152M 863M 15% /boot
tmpfs tmpfs 796M 16K 796M 1% /run/user/42
tmpfs tmpfs 796M 3.5M 792M 1% /run/user/0
/dev/mapper/xiaofeng xfs 100G 747M 100G 1% /root/new_disk/vdo/xiaofeng五 开机自动挂载
1 查看VDO卷的UUID blkid /dev/mapper/xiaofeng
[root@linuxprobe ~]# blkid /dev/mapper/xiaofeng
/dev/mapper/xiaofeng: UUID="6e1d7281-c010-4b8b-9044-b157d09a8bbd" TYPE="xfs"2 编辑/etc/fstab vim /etc/fstab
[root@linuxprobe ~]# vim /etc/fstab在最后加上一行
UUID=6e1d7281-c010-4b8b-9044-b157d09a8bbd /root/new_disk/vdo/xiaofeng xfs defaults,_netdev 0 0
#
# /etc/fstab
# Created by anaconda on Tue Jun 8 06:02:20 2021
#
# Accessible filesystems, by reference, are maintained under '/dev/disk/'.
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info.
#
# After editing this file, run 'systemctl daemon-reload' to update systemd
# units generated from this file.
#
/dev/mapper/rhel-root / xfs defaults 0 0
UUID=2c1949d3-5cd8-4b71-b60d-8885bfc326e0 /boot xfs defaults 0 0
/dev/mapper/rhel-swap swap swap defaults 0 0
UUID=6e1d7281-c010-4b8b-9044-b157d09a8bbd /root/new_disk/vdo/xiaofeng xfs defaults,_netdev 0 0
~ 3 挂载所有/etc/fstab中的设备 mount -a
[root@linuxprobe ~]# mount -a4 重启系统 reboot
[root@linuxprobe ~]# reboot5 查看是否挂载成功 vdostats –human-readable
[root@linuxprobe ~]# vdostats --human-readable
Device Size Used Available Use% Space saving%
/dev/mapper/xiaofeng 10.0G 4.0G 6.0G 40% 99%6 查看是否挂载成功 df -hT
[root@linuxprobe ~]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
devtmpfs devtmpfs 3.9G 0 3.9G 0% /dev
tmpfs tmpfs 3.9G 0 3.9G 0% /dev/shm
tmpfs tmpfs 3.9G 9.9M 3.9G 1% /run
tmpfs tmpfs 3.9G 0 3.9G 0% /sys/fs/cgroup
/dev/mapper/rhel-root xfs 44G 4.1G 40G 10% /
/dev/sda1 xfs 1014M 152M 863M 15% /boot
/dev/mapper/xiaofeng xfs 100G 747M 100G 1% /root/new_disk/vdo/xiaofeng
tmpfs tmpfs 796M 16K 796M 1% /run/user/42
tmpfs tmpfs 796M 3.5M 792M 1% /run/user/0发现已经有挂载信息，大功告成！
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