一.概念
LVM是逻辑盘卷管理（Logical Volume Manager）的简称，它是Linux环境下对磁盘分区进行管理的一种机制，LVM是建立在硬盘和分区之上的一个逻辑层，来提高磁盘分区管理的灵活性。
LVM的工作原理其实很简单，它就是通过将底层的物理硬盘抽象的封装起来，然后以逻辑卷的方式呈现给上层应用。在传统的磁盘管理机制中，我们的上层应用是直接访问文件系统，从而对底层的物理硬盘进行读取，而在LVM中，其通过对底层的硬盘进行封装，当我们对底层的物理硬盘进行操作时，其不再是针对于分区进行操作，而是通过一个叫做逻辑卷的东西来对其进行底层的磁盘管理操作。比如说我增加一个物理硬盘，这个时候上层的服务是感觉不到的，因为呈现给上层服务的是以逻辑卷的方式。LVM最大的特点就是可以对磁盘进行动态管理。因为逻辑卷的大小是可以动态调整的，而且不会丢失现有的数据。如果我们新增加了硬盘，其也不会改变现有上层的逻辑卷。作为一个动态磁盘管理机制，逻辑卷技术大大提高了磁盘管理的灵活性。
PV（Physical Volume）–物理卷物理卷在逻辑卷管理中处于最底层，它可以是实际物理硬盘上的分区，也可以是整个物理硬盘，也可以是raid设备。
VG（Volumne Group）–卷组卷组建立在物理卷之上，一个卷组中至少要包括一个物理卷，在卷组建立之后可动态添加物理卷到卷组中。一个逻辑卷管理系统工程中可以只有一个卷组，也可以拥有多个卷组。
LV（Logical Volume）–逻辑卷逻辑卷建立在卷组之上，卷组中的未分配空间可以用于建立新的逻辑卷，逻辑卷建立后可以动态地扩展和缩小空间。系统中的多个逻辑卷可以属于同一个卷组，也可以属于不同的多个卷组。
二.基础操作
1.PV阶段
命令：
pvcreate ：将实体 partition 创建成为 PV ；
pvscan ：搜寻目前系统里面任何具有 PV 的磁盘；
pvdisplay ：显示出目前系统上面的 PV 状态；
pvremove ：将 PV 属性移除，让该 partition 不具有 PV 属性。
创建pv
[[email protected] ~]# pvcreate /dev/sd[b-e]
Physical volume "/dev/sdb" successfully created.
Physical volume "/dev/sdc" successfully created.
Physical volume "/dev/sdd" successfully created.
Physical volume "/dev/sde" successfully created.查看pv
[[email protected] ~]# pvscan
PV /dev/sda2 VG centos lvm2 [<119.00 GiB / 4.00 MiB free]
PV /dev/sdd lvm2 [10.00 GiB]
PV /dev/sdc lvm2 [10.00 GiB]
PV /dev/sde lvm2 [10.00 GiB]
PV /dev/sdb lvm2 [10.00 GiB]
Total: 5 [<159.00 GiB] / in use: 1 [<119.00 GiB] / in no VG: 4 [40.00 GiB]
[[email protected] ~]# pvdisplay /dev/sd[b-e]
"/dev/sdd" is a new physical volume of "10.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdd
VG Name
PV Size 10.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID 7DY4J9-WfXO-3Xy7-hVY5-73se-3XaT-LZ4TD0
"/dev/sdc" is a new physical volume of "10.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdc
VG Name
PV Size 10.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID kPo6FF-KVEm-PIUT-UW6G-pQUL-vHrN-X61EAc
"/dev/sde" is a new physical volume of "10.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sde
VG Name
PV Size 10.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID wPD6Ug-QMWl-JH1e-QvE3-PsJ8-V34E-dl6nSl
"/dev/sdb" is a new physical volume of "10.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdb
VG Name
PV Size 10.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID tBwxI2-JyFl-1Fsg-R07f-7qT1-yd57-0e756a2.VG阶段
命令：
vgcreate ：创建 VG 的指令
vgscan ：搜寻系统上面是否有 VG 存在
vgdisplay ：显示目前系统上面的 VG 状态
vgextend ：在 VG 内增加额外的 PV
vgreduce ：在 VG 内移除 PV
vgchange ：设置 VG 是否启动 （active）
vgremove ：删除一个 VG 啊！创建VG
[[email protected] ~]# vgcreate -s 1G wakamizuvg /dev/sd[b-e]
Volume group "wakamizuvg" successfully created查看vg
[[email protected] ~]# vgscan
Reading volume groups from cache.
Found volume group "wakamizuvg" using metadata type lvm2
Found volume group "centos" using metadata type lvm2
[[email protected] ~]# pvscan
PV /dev/sdb VG wakamizuvg lvm2 [9.00 GiB / 9.00 GiB free]
PV /dev/sdc VG wakamizuvg lvm2 [9.00 GiB / 9.00 GiB free]
PV /dev/sdd VG wakamizuvg lvm2 [9.00 GiB / 9.00 GiB free]
PV /dev/sde VG wakamizuvg lvm2 [9.00 GiB / 9.00 GiB free]
PV /dev/sda2 VG centos lvm2 [<119.00 GiB / 4.00 MiB free]
Total: 5 [<155.00 GiB] / in use: 5 [<155.00 GiB] / in no VG: 0 [0 ]
[[email protected] ~]# vgdisplay wakamizuvg
--- Volume group ---
VG Name wakamizuvg
System ID
Format lvm2
Metadata Areas 4
Metadata Sequence No 1
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 0
Open LV 0
Max PV 0
Cur PV 4
Act PV 4
VG Size 36.00 GiB
PE Size 1.00 GiB
Total PE 36
Alloc PE / Size 0 / 0
Free PE / Size 36 / 36.00 GiB
VG UUID WmRALB-yWeR-TGg3-hjNY-31JI-EOji-Wwfj1x增加VG容量
[[email protected] ~]#vgextend wakamizuvg /dev/vdax3.LV阶段
命令：
vcreate ：创建 LV
lvscan ：查询系统上面的 LV
lvdisplay ：显示系统上面的 LV 状态
lvextend ：在 LV 里面增加容量
lvreduce ：在 LV 里面减少容量
lvremove ：删除一个 LV
lvresize ：对 LV 进行容量大小的调整
创建LV
[[email protected] ~]# lvcreate -L 2G -n wakamizulv wakamizuvg
Logical volume "wakamizulv" created.查看LV
[[email protected] ~]# lvscan
ACTIVE '/dev/wakamizuvg/wakamizulv' [2.00 GiB] inherit
ACTIVE '/dev/centos/swap' [3.75 GiB] inherit
ACTIVE '/dev/centos/home' [65.24 GiB] inherit
ACTIVE '/dev/centos/root' [50.00 GiB] inherit
[[email protected] ~]# lvdisplay /dev/wakamizuvg/wakamizulv
--- Logical volume ---
LV Path /dev/wakamizuvg/wakamizulv
LV Name wakamizulv
VG Name wakamizuvg
LV UUID S5RzRp-xiee-sc6K-LfLx-PkwH-qV28-t1N1aw
LV Write Access read/write
LV Creation host, time server01, 2020-07-08 20:10:00 +0800
LV Status available
# open 0
LV Size 2.00 GiB
Current LE 2
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:34.初始化文件系统并挂载
[[email protected] ~]# mkfs.xfs /dev/wakamizuvg/wakamizulv
meta-data=/dev/wakamizuvg/wakamizulv isize=512 agcount=4, agsize=131072 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0, sparse=0
data = bsize=4096 blocks=524288, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
[[email protected] ~]# mount /dev/wakamizuvg/wakamizulv /tmp/test
[[email protected] ~]# df -Th /tmp/test
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/wakamizuvg-wakamizulv xfs 2.0G 33M 2.0G 2% /tmp/test5.扩大LV容量（要先看VG剩余容量是否足够，不够的话添加硬盘加入PV）
[[email protected] ~]# lvresize -L +1G /dev/wakamizuvg/wakamizulv
Size of logical volume wakamizuvg/wakamizulv changed from 2.00 GiB (2 extents) to 3.00 GiB (3 extents).
Logical volume wakamizuvg/wakamizulv successfully resized.
[[email protected] ~]# lvscan
ACTIVE '/dev/wakamizuvg/wakamizulv' [3.00 GiB] inherit
ACTIVE '/dev/centos/swap' [3.75 GiB] inherit
ACTIVE '/dev/centos/home' [65.24 GiB] inherit
ACTIVE '/dev/centos/root' [50.00 GiB] inherit
[[email protected] ~]# xfs_info /tmp/test
meta-data=/dev/mapper/wakamizuvg-wakamizulv isize=512 agcount=4, agsize=131072 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=524288, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
[[email protected] ~]# xfs_growfs /tmp/test
meta-data=/dev/mapper/wakamizuvg-wakamizulv isize=512 agcount=4, agsize=131072 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=524288, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 524288 to 786432
[[email protected] ~]# df -Th /tmp/test
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/wakamizuvg-wakamizulv xfs 3.0G 33M 3.0G 2% /tmp/test三.lvm快照
1.创建快照
[[email protected] ~]# lvcreate -s -l 5 -n wakamizusnap1 /dev/wakamizuvg/wakamizulv
Logical volume "wakamizusnap1" created.
[[email protected] ~]# lvdisplay /dev/wakamizuvg/wakamizusnap1
--- Logical volume ---
LV Path /dev/wakamizuvg/wakamizusnap1
LV Name wakamizusnap1
VG Name wakamizuvg
LV UUID vbWYJr-sXp0-mObl-F18J-ch0M-oJJn-mqPJV3
LV Write Access read/write
LV Creation host, time server01, 2020-07-08 20:58:31 +0800
LV snapshot status active destination for wakamizulv
LV Status available
# open 0
LV Size 4.00 GiB
Current LE 4
COW-table size 5.00 GiB
COW-table LE 5
Allocated to snapshot 0.00%
Snapshot chunk size 4.00 KiB
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:6
[[email protected] ~]# mount -o nouuid /dev/wakamizuvg/wakamizusnap1 /tmp/test/
[[email protected] ~]# df -Th /tmp/test*
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/wakamizuvg-wakamizusnap1 xfs 3.0G 33M 3.0G 2% /tmp/test
/dev/mapper/wakamizuvg-wakamizulv xfs 3.0G 33M 3.0G 2% /tmp/testlv2.在/tmp/testlv里面创造新数据再次查询容量
[[email protected] tmp]# xfsdump -l 0 -L lvm1 -M lvm1 -f /root/lvm.dump /tmp/test
xfsdump: using file dump (drive_simple) strategy
xfsdump: version 3.1.7 (dump format 3.0) - type ^C for status and control
xfsdump: level 0 dump of server01:/tmp/test
xfsdump: dump date: Wed Jul 8 21:26:29 2020
xfsdump: session id: 49913f6b-356f-4cc4-98b5-90124c52c18f
xfsdump: session label: "lvm1"
xfsdump: ino map phase 1: constructing initial dump list
xfsdump: ino map phase 2: skipping (no pruning necessary)
xfsdump: ino map phase 3: skipping (only one dump stream)
xfsdump: ino map construction complete
xfsdump: estimated dump size: 21120 bytes
xfsdump: positioned at media file 0: dump 0, stream 0
xfsdump: ERROR: media contains valid xfsdump but does not support append
xfsdump: dump size (non-dir files) : 0 bytes
xfsdump: NOTE: dump interrupted: 0 seconds elapsed: may resume later using -R option
xfsdump: Dump Summary:
xfsdump: stream 0 /root/lvm.dump ERROR (operator error or resource exhaustion)
xfsdump: Dump Status: INTERRUPT4.恢复数据
[[email protected] tmp]# umount /tmp/testlv/
[[email protected] tmp]# mkfs.xfs -f /dev/wakamizuvg/wakamizulv
meta-data=/dev/wakamizuvg/wakamizulv isize=512 agcount=4, agsize=262144 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0, sparse=0
data = bsize=4096 blocks=1048576, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
[[email protected] tmp]# mount /dev/wakamizuvg/wakamizulv /tmp/testlv
[[email protected] tmp]# xfsrestore -f /root/lvm.dump -L lvm1 /tmp/testlv/
xfsrestore: using file dump (drive_simple) strategy
xfsrestore: version 3.1.7 (dump format 3.0) - type ^C for status and control
xfsrestore: searching media for dump
xfsrestore: examining media file 0
xfsrestore: found dump matching specified label:
xfsrestore: hostname: server01
xfsrestore: mount point: /tmp/test
xfsrestore: volume: /dev/mapper/wakamizuvg-wakamizusnap1
xfsrestore: session time: Wed Jul 8 21:12:17 2020
xfsrestore: level: 0
xfsrestore: session label: "lvm1"
xfsrestore: media label: "lvm1"
xfsrestore: file system id: 42b30127-a562-4777-b468-5d09b73f0625
xfsrestore: session id: 27ea9e6e-4463-46c5-9af9-3219b0895af0
xfsrestore: media id: 7e12869b-5550-42ac-b291-e75c4bd9823b
xfsrestore: using online session inventory
xfsrestore: searching media for directory dump
xfsrestore: reading directories
xfsrestore: 1 directories and 0 entries processed
xfsrestore: directory post-processing
xfsrestore: restore complete: 0 seconds elapsed
xfsrestore: Restore Summary:
xfsrestore: stream 0 /root/lvm.dump OK (success)
xfsrestore: Restore Status: SUCCESS