Linux常用命令-lvm

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命令

lvm

描述

LVM2 tools
逻辑卷管理器LVM可以通过物理设备来创建虚拟块设备,可以动态的调整分区大小,更便于管理多块磁盘

用法

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lvm [command|file]
lvm help [command]

选项

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lvm子命令
pv相关命令:
  pvchange        更改pv属性
  pvresize        调整pv大小
  pvck            检查pv一致性
  pvcreate        创建pv
  pvdisplay       显示pv属性
  pvmove          迁移pv数据
  pvremove        删除pv
  pvs             显示pv属性
  pvscan          显示所有pv

vg相关命令:
  vgcfgbackup     备份vg配置
  vgcfgrestore    还原vg配置
  vgchange        更改vg属性
  vgck            检查vg一致性
  vgconvert       更改vg元数据格式
  vgcreate        创建vg
  vgdisplay       显示vg信息
  vgexport        在系统中取消vg
  vgextend        添加pv到vg
  vgimport        在系统中注册vg
  vgimportclone   从克隆的pv导入vg
  vgmerge         合并vg
  vgmknodes       在/dev中为vg创建特殊文件
  vgreduce        从vg中移除pv
  vgremove        删除vg
  vgrename        重命名vg
  vgs             显示vg属性
  vgscan          显示所有vg
  vgsplit         将pv移动到新的或现有的vg中

lv相关命令:
  lvchange        更改lv属性
  lvconvert       更改lv格式
  lvcreate        创建lv
  lvdisplay       显示lv属性
  lvextend        扩容lv
  lvreduce        压缩lv
  lvremove        删除lv
  lvrename        重命名lv
  lvresize        调整lv大小
  lvs             显示lv属性
  lvscan          显示所有lv

注意

1.对磁盘或分区操作前,一定要确认盘符,路径,分区等相关信息,避免误操作导致数据丢失
2.ext4文件系统支持增大和减小分区空间,但是xfs只支持增大,不支持减小空间,建议预先分配xfs分区时尽可能小,后续再逐步增加
3.取消lvm分区挂载时一定要删除fstab中的配置,否则会导致系统重启后无法启动

示例

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# 部分lvm子命令可以独立使用,如`lvm vgs`可以直接执行`vgs`命令
$ lvm vgs
  VG     #PV #LV #SN Attr   VSize   VFree
  centos   1   2   0 wz--n- <19.00g    0 
$ vgs
  VG     #PV #LV #SN Attr   VSize   VFree
  centos   1   2   0 wz--n- <19.00g    0 
# 可以看到vgs是lvm命令的软链接
$ ll /usr/sbin/vgs
lrwxrwxrwx. 1 root root 3 May 21 02:28 /usr/sbin/vgs -> lvm
# 其他相关的子命令vg*,pv*,lv*多数都是lvm命令的软链接
$ ll /usr/sbin/vg*
lrwxrwxrwx. 1 root root 3 May 21 02:28 /usr/sbin/vgcfgbackup -> lvm
lrwxrwxrwx. 1 root root 3 May 21 02:28 /usr/sbin/vgcfgrestore -> lvm
lrwxrwxrwx. 1 root root 3 May 21 02:28 /usr/sbin/vgchange -> lvm
lrwxrwxrwx. 1 root root 3 May 21 02:28 /usr/sbin/vgck -> lvm
lrwxrwxrwx. 1 root root 3 May 21 02:28 /usr/sbin/vgconvert -> lvm
lrwxrwxrwx. 1 root root 3 May 21 02:28 /usr/sbin/vgcreate -> lvm
...
$ ll /usr/sbin/pv*
$ ll /usr/sbin/lv*

# 新加了sdb,sdc,sdd三块硬盘
$ lsblk
NAME            MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda               8:0    0  20G  0 disk 
├─sda1            8:1    0   1G  0 part /boot
└─sda2            8:2    0  19G  0 part 
  ├─centos-root 253:0    0  17G  0 lvm  /
  └─centos-swap 253:1    0   2G  0 lvm  [SWAP]
sdb               8:16   0   5G  0 disk 
sdc               8:32   0  10G  0 disk 
sdd               8:48   0  20G  0 disk 
# 当前lvm分区情况如下
$ pvs
  PV         VG     Fmt  Attr PSize   PFree
  /dev/sda2  centos lvm2 a--  <19.00g    0 
$ vgs
  VG     #PV #LV #SN Attr   VSize   VFree
  centos   1   2   0 wz--n- <19.00g    0 
$ lvs
  LV   VG     Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  root centos -wi-ao---- <17.00g 
  swap centos -wi-ao----   2.00g 
# 创建pv
$ pvcreate /dev/sdb
  Physical volume "/dev/sdb" successfully created.
# 查看pv
$ pvs /dev/sdb
  PV         VG Fmt  Attr PSize PFree
  /dev/sdb      lvm2 ---  5.00g 5.00g
$ pvdisplay /dev/sdb
  "/dev/sdb" is a new physical volume of "5.00 GiB"
  --- NEW Physical volume ---
  PV Name               /dev/sdb
  VG Name               
  PV Size               5.00 GiB
  Allocatable           NO
  PE Size               0   
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               9vPLxu-s0qb-Ko1D-QsB9-maB1-R0xR-liIDA8
# 创建vg
$ vgcreate vg_data /dev/sdb
  Volume group "vg_data" successfully created
# 查看vg
$ vgs vg_data
  VG      #PV #LV #SN Attr   VSize  VFree 
  vg_data   1   0   0 wz--n- <5.00g <5.00g
$ vgdisplay vg_data
  --- Volume group ---
  VG Name               vg_data
  System ID             
  Format                lvm2
  Metadata Areas        1
  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                1
  Act PV                1
  VG Size               <5.00 GiB
  PE Size               4.00 MiB
  Total PE              1279
  Alloc PE / Size       0 / 0   
  Free  PE / Size       1279 / <5.00 GiB
  VG UUID               BJLto4-ZwX3-BGdN-mutx-5n15-GDb2-tdqpTC
# 创建lv
$ lvcreate -l +100%FREE -n lv_data vg_data
  Logical volume "lv_data" created.
# 查看lv,注意查看指定lv时指定的是vg的名称或者指定完整路径
$ lvs vg_data
  LV      VG      Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  lv_data vg_data -wi-a----- <5.00g
$ lvs /dev/vg_data/lv_data
  LV      VG      Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  lv_data vg_data -wi-a----- <5.00g 
$ lvdisplay vg_data
  --- Logical volume ---
  LV Path                /dev/vg_data/lv_data
  LV Name                lv_data
  VG Name                vg_data
  LV UUID                xeWHZw-OjkW-Dtbm-TnSl-5ahH-oxVK-qAfTae
  LV Write Access        read/write
  LV Creation host, time centos7, 2021-08-02 21:42:31 +0800
  LV Status              available
  # open                 0
  LV Size                <5.00 GiB
  Current LE             1279
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:2
# 格式化lv并挂载到/data分区
$ mkfs.xfs /dev/mapper/vg_data-lv_data 
meta-data=/dev/mapper/vg_data-lv_data isize=512    agcount=4, agsize=327424 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0, sparse=0
data     =                       bsize=4096   blocks=1309696, 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
$ lsblk /dev/sdb
NAME              MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sdb                 8:16   0   5G  0 disk 
└─vg_data-lv_data 253:2    0   5G  0 lvm  
# 查看分区的uuid
$ blkid /dev/sdb
/dev/sdb: UUID="9vPLxu-s0qb-Ko1D-QsB9-maB1-R0xR-liIDA8" TYPE="LVM2_member" 
$ blkid /dev/mapper/vg_data-lv_data
/dev/mapper/vg_data-lv_data: UUID="ebd64a45-66f6-4826-8b3c-81d16d40e392" TYPE="xfs" 
$ mkdir /data
$ mount /dev/mapper/vg_data-lv_data /data/
$ df -hT /data
Filesystem                  Type  Size  Used Avail Use% Mounted on
/dev/mapper/vg_data-lv_data xfs   5.0G   33M  5.0G   1% /data
# 添加挂载信息到fstab,开机自动挂载
$ echo "/dev/mapper/vg_data-lv_data     /data   xfs     defaults    0 0" >> /etc/fstab
# 取消挂载
$ umount /data
# 删除lv
$ lvremove /dev/mapper/vg_data-lv_data 
Do you really want to remove active logical volume vg_data/lv_data? [y/n]: y
  Logical volume "lv_data" successfully removed
# 删除vg
$ vgremove vg_data 
  Volume group "vg_data" successfully removed
# 删除pv
$ pvremove /dev/sdb
  Labels on physical volume "/dev/sdb" successfully wiped.

# 重复以上步骤到自动挂载,然后进行如下的扩容操作
# 注意以下操作为全盘扩容,并没有对新硬盘sdc进行分区,适用于虚拟机环境,即按需添加一块对应大小的硬盘进行全盘扩容
$ df -hT /data
Filesystem                  Type  Size  Used Avail Use% Mounted on
/dev/mapper/vg_data-lv_data xfs   5.0G   33M  5.0G   1% /data
$ lsblk /dev/sdb
NAME              MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sdb                 8:16   0   5G  0 disk 
└─vg_data-lv_data 253:2    0   5G  0 lvm  /data
# 添加pv-sdc
$ pvcreate /dev/sdc
  Physical volume "/dev/sdc" successfully created.
$ pvs
  PV         VG      Fmt  Attr PSize   PFree  
  /dev/sda2  centos  lvm2 a--  <19.00g      0 
  /dev/sdb   vg_data lvm2 a--   <5.00g      0 
  /dev/sdc   vg_data lvm2 a--  <10.00g <10.00g
# 添加sdc到vg_data
$ vgextend vg_data /dev/sdc
  Volume group "vg_data" successfully extended
$ vgs vg_data 
  VG      #PV #LV #SN Attr   VSize  VFree  
  vg_data   2   1   0 wz--n- 14.99g <10.00g
# 扩展lv_data空间,即扩容/data分区
$ lvextend -r -l +100%FREE /dev/mapper/vg_data-lv_data
  Size of logical volume vg_data/lv_data changed from <5.00 GiB (1279 extents) to 14.99 GiB (3838 extents).
  Logical volume vg_data/lv_data successfully resized.
meta-data=/dev/mapper/vg_data-lv_data isize=512    agcount=4, agsize=327424 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0 spinodes=0
data     =                       bsize=4096   blocks=1309696, 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 1309696 to 3930112
# 查看/data分区由5G增加到了15G
$ df -hT /data
Filesystem                  Type  Size  Used Avail Use% Mounted on
/dev/mapper/vg_data-lv_data xfs    15G   33M   15G   1% /data
$ lsblk /dev/sdb /dev/sdc
NAME              MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sdb                 8:16   0   5G  0 disk 
└─vg_data-lv_data 253:2    0  15G  0 lvm  /data
sdc                 8:32   0  10G  0 disk 
└─vg_data-lv_data 253:2    0  15G  0 lvm  /data

# 如果是物理机或者添加了一块较大的硬盘,可以考虑先分区再扩容,避免磁盘空间的浪费
# 如下操作为分区扩容,从sdd硬盘中划分出10G的分区,扩容到/data
# 以下fdisk命令为非交互式分区命令,从sdd中划分一个10G的分区sdd1
$ echo -e "n\np\n1\n\n+10G\nt\n8e\nw\n" | fdisk /dev/sdd
$ lsblk /dev/sdd
NAME   MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sdd      8:48   0  20G  0 disk 
└─sdd1   8:49   0  10G  0 part 
$ pvcreate /dev/sdd1
  Physical volume "/dev/sdd1" successfully created.
$ vgextend vg_data /dev/sdd1
  Volume group "vg_data" successfully extended
$ vgs vg_data 
  VG      #PV #LV #SN Attr   VSize   VFree  
  vg_data   3   1   0 wz--n- <24.99g <10.00g
$ lvextend -r -l +100%FREE /dev/mapper/vg_data-lv_data
  Size of logical volume vg_data/lv_data changed from 14.99 GiB (3838 extents) to <24.99 GiB (6397 extents).
  Logical volume vg_data/lv_data successfully resized.
# /data分区大小由15G增加到了25G
$ df -hT /data
Filesystem                  Type  Size  Used Avail Use% Mounted on
/dev/mapper/vg_data-lv_data xfs    25G   34M   25G   1% /data

# 注意xfs文件系统的lvm分区只能增加,不能减小
$ lvreduce -r -L 20G /dev/vg_data/lv_data 
  Size of logical volume vg_data/lv_data unchanged from 20.00 GiB (5120 extents).
  Logical volume vg_data/lv_data successfully resized.
fsadm: Xfs filesystem shrinking is unsupported.
  /usr/sbin/fsadm failed: 1