Linux系统——lvm逻辑卷

一、lvm逻辑卷

Logical Volume Managemant
优势: 在线扩容、缩容

1、lvm操作流程

2、操作指令

• 查看PV

[root@martin-host ~]# pvscan PV /dev/sda2   VG centos          lvm2 [19.21 GiB / 0    free]Total: 1 [19.21 GiB] / in use: 1 [19.21 GiB] / in no VG: 0 [0   ]

• 查看VG

[root@martin-host ~]# pvscan PV /dev/sda2   VG centos          lvm2 [19.21 GiB / 0    free]Total: 1 [19.21 GiB] / in use: 1 [19.21 GiB] / in no VG: 0 [0   ]
[root@martin-host ~]# 
[root@martin-host ~]# vgscan Reading volume groups from cache.Found volume group "centos" using metadata type lvm2

[root@martin-host ~]# vgdisplay centos --- Volume group ---VG Name               centosSystem ID             Format                lvm2Metadata Areas        1Metadata Sequence No  3VG Access             read/writeVG Status             resizableMAX LV                0Cur LV                2Open LV               2Max PV                0Cur PV                1Act PV                1VG Size               19.21 GiBPE Size               4.00 MiBTotal PE              4919Alloc PE / Size       4919 / 19.21 GiBFree  PE / Size       0 / 0   VG UUID               Pgh5Zq-mdOk-I64Z-NDPa-XkUb-RpsR-JRzCsk

• 查看lv

[root@martin-host ~]# lvscan ACTIVE            '/dev/centos/swap' [1.00 GiB] inheritACTIVE            '/dev/centos/root' [18.21 GiB] inherit[root@martin-host ~]# ls -l /dev/centos/root 
lrwxrwxrwx 1 root root 7 10月 11 09:02 /dev/centos/root -> ../dm-0[root@martin-host ~]# ls -l /dev/dm-0 
brw-rw---- 1 root disk 253, 0 10月 11 09:02 /dev/dm-0

二、逻辑卷操作

1、创建逻辑卷

1.1 /dev/cloud/openstack 5G xfs /cloud/openstack

• 确认裸设备

[root@martin-host ~]# blkid /dev/sde
[root@martin-host ~]# blkid /dev/sdf

• 创建pv物理卷

[root@martin-host ~]# pvcreate /dev/sde /dev/sdfPhysical volume "/dev/sde" successfully created.Physical volume "/dev/sdf" successfully created.
[root@martin-host ~]# 
[root@martin-host ~]# pvscan PV /dev/sda2   VG centos          lvm2 [19.21 GiB / 0    free]PV /dev/sdf                       lvm2 [20.00 GiB]PV /dev/sde                       lvm2 [20.00 GiB]Total: 3 [59.21 GiB] / in use: 1 [19.21 GiB] / in no VG: 2 [40.00 GiB]

• 创建卷组，名称cloud

[root@martin-host ~]# vgcreate cloud /dev/sde /dev/sdfVolume group "cloud" successfully created[root@martin-host ~]# vgdisplay cloud --- Volume group ---VG Name               cloudSystem ID             Format                lvm2Metadata Areas        2Metadata Sequence No  1VG Access             read/writeVG Status             resizableMAX LV                0Cur LV                0Open LV               0Max PV                0Cur PV                2Act PV                2VG Size               39.99 GiBPE Size               4.00 MiBTotal PE              10238Alloc PE / Size       0 / 0   Free  PE / Size       10238 / 39.99 GiBVG UUID               2cyeQa-pxwF-TDQ3-3buR-04Tc-My5z-WINKYY

• 创建逻辑卷，名称为openstack

[root@martin-host ~]# lvcreate -L 5G -n openstack cloudLogical volume "openstack" created.
[root@martin-host ~]# 
[root@martin-host ~]# lvscan ACTIVE            '/dev/cloud/openstack' [5.00 GiB] inherit

• 挂载使用

[root@martin-host ~]# mkfs -t xfs /dev/cloud/openstack [root@martin-host ~]# 
[root@martin-host ~]# mkdir -p /cloud/openstack[root@martin-host ~]# tail -n 1 /etc/fstab
/dev/cloud/openstack	/cloud/openstack	xfs	defaults	0 0
[root@martin-host ~]# 
[root@martin-host ~]# mount -a[root@martin-host ~]# df -hT 
文件系统                    类型      容量  已用  可用 已用% 挂载点
/dev/mapper/cloud-openstack xfs       5.0G   33M  5.0G    1% /cloud/openstack[root@martin-host ~]# touch /cloud/openstack/{1..20}
[root@martin-host ~]# ls /cloud/openstack/
1  10  11  12  13  14  15  16  17  18  19  2  20  3  4  5  6  7  8  9
[root@martin-host ~]# 

1.2 /dev/cloud/docker 10G ext4 /cloud/docker

[root@martin-host ~]# lvcreate -L 10G -n docker cloudLogical volume "docker" created.[root@martin-host ~]# lvscan ACTIVE            '/dev/cloud/openstack' [5.00 GiB] inheritACTIVE            '/dev/cloud/docker' [10.00 GiB] inheritACTIVE            '/dev/centos/swap' [1.00 GiB] inheritACTIVE            '/dev/centos/root' [18.21 GiB] inherit[root@martin-host ~]# df -hT | grep cloud
/dev/mapper/cloud-openstack xfs       5.0G   33M  5.0G    1% /cloud/openstack
/dev/mapper/cloud-docker    ext4      9.8G   37M  9.2G    1% /cloud/docker

2、逻辑卷扩容

2.1 扩容流程

1、确认卷组有足够的剩余空间
2、先扩展逻辑卷的物理大小
3、再扩展逻辑卷的文件系统大小

2.2 需求一：扩容ext4文件系统的逻辑卷

[root@martin-host ~]# blkid /dev/cloud/docker
/dev/cloud/docker: UUID="722ade99-6f1d-40a9-8731-2097b6b8e385" TYPE="ext4" 

• 查看卷组的剩余空间

[root@martin-host ~]# vgdisplay cloud | grep -i freeFree  PE / Size       6398 / 24.99 GiB

• 扩展逻辑卷物理大小

[root@martin-host ~]# lvextend -L 15G /dev/cloud/docker Size of logical volume cloud/docker changed from 10.00 GiB (2560 extents) to 15.00 GiB (3840 extents).Logical volume cloud/docker successfully resized.
[root@martin-host ~]# 
[root@martin-host ~]# lvscan ACTIVE            '/dev/cloud/openstack' [5.00 GiB] inheritACTIVE            '/dev/cloud/docker' [15.00 GiB] inheritACTIVE            '/dev/centos/swap' [1.00 GiB] inheritACTIVE            '/dev/centos/root' [18.21 GiB] inherit
[root@martin-host ~]# 
[root@martin-host ~]# df -hT | grep "docker"
/dev/mapper/cloud-docker    ext4      9.8G   37M  9.2G    1% /cloud/docker

• 扩展文件系统大小

// resize2fs：只适用于ext文件系统
[root@martin-host ~]# resize2fs /dev/cloud/docker 
resize2fs 1.42.9 (28-Dec-2013)
Filesystem at /dev/cloud/docker is mounted on /cloud/docker; on-line resizing required
old_desc_blocks = 2, new_desc_blocks = 2
The filesystem on /dev/cloud/docker is now 3932160 blocks long.[root@martin-host ~]# 
[root@martin-host ~]# lvscan | grep "docker"ACTIVE            '/dev/cloud/docker' [15.00 GiB] inherit[root@martin-host ~]# df -hT | grep "docker"
/dev/mapper/cloud-docker    ext4       15G   41M   14G    1% /cloud/docker[root@martin-host ~]# ls /cloud/docker/
file01  file010  file02  file03  file04  file05  file06  file07  file08  file09 

2.3 需求二：扩展xfs文件系统的逻辑卷

[root@martin-host ~]# blkid /dev/cloud/openstack 
/dev/cloud/openstack: UUID="6ef5d418-8fa7-410f-8447-d01f636a791c" TYPE="xfs" 
[root@martin-host ~]# 
[root@martin-host ~]# vgdisplay cloud | grep -i freeFree  PE / Size       5118 / 19.99 GiB
[root@martin-host ~]# 
[root@martin-host ~]# lvextend -L 20G /dev/cloud/openstack Size of logical volume cloud/openstack changed from 5.00 GiB (1280 extents) to 20.00 GiB (5120 extents).Logical volume cloud/openstack successfully resized.
[root@martin-host ~]# // xfs_growfs: 适用于xfs文件系统
[root@martin-host ~]# xfs_growfs /dev/cloud/openstack 
meta-data=/dev/mapper/cloud-openstack isize=512    agcount=4, agsize=327680 blks=                       sectsz=512   attr=2, projid32bit=1=                       crc=1        finobt=0 spinodes=0
data     =                       bsize=4096   blocks=1310720, 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 1310720 to 5242880
[root@martin-host ~]# 
[root@martin-host ~]# 
[root@martin-host ~]# lvscan | grep openstackACTIVE            '/dev/cloud/openstack' [20.00 GiB] inherit
[root@martin-host ~]# 
[root@martin-host ~]# df -hT | grep opensta
/dev/mapper/cloud-openstack xfs        20G   33M   20G    1% /cloud/openstack
[root@martin-host ~]# 
[root@martin-host ~]# 
[root@martin-host ~]# ls /cloud/openstack/
1  10  11  12  13  14  15  16  17  18  19  2  20  3  4  5  6  7  8  9

2.2.4 需求三：扩展逻辑卷(卷组空间不足)

[root@martin-host ~]# vgdisplay cloud | grep -i freeFree  PE / Size       1278 / 4.99 GiB

• 扩容卷组的容量

[root@martin-host ~]# pvcreate /dev/sdgPhysical volume "/dev/sdg" successfully created.[root@martin-host ~]# vgextend cloud /dev/sdg Volume group "cloud" successfully extended[root@martin-host ~]# vgdisplay cloud | grep -i freeFree  PE / Size       6397 / <24.99 GiB

• 扩展逻辑卷

[root@martin-host ~]# lvextend -L 20G /dev/cloud/docker 
[root@martin-host ~]# resize2fs /dev/cloud/docker

3、逻辑卷缩容

注意：
1、谨慎操作、数据无价
2、xfs文件系统不支持缩减

3.1 缩容流程

1、卸载设备， 不支持在线
2、先缩减文件系统大小
3、再缩减逻辑卷的物理大小

3.2 需求一：将逻辑卷docker缩减到5G

• 将数据备份

[root@martin-host ~]# tar czf /backup/docker.tar.gz   /cloud/docker/ 
tar: 从成员名中删除开头的“/”
[root@martin-host ~]# 

• 卸载逻辑卷

[root@martin-host ~]# umount /dev/cloud/docker
[root@martin-host ~]# 
[root@martin-host ~]# df -hT | grep "docker"
[root@martin-host ~]# 

• 检查文件系统是否有损坏

[root@martin-host ~]# e2fsck -f /dev/cloud/docker 
e2fsck 1.42.9 (28-Dec-2013)
第一步: 检查inode,块,和大小
第二步: 检查目录结构
第3步: 检查目录连接性
Pass 4: Checking reference counts
第5步: 检查簇概要信息
/dev/cloud/docker: 21/1310720 files (0.0% non-contiguous), 126311/5242880 blocks

• 先缩减文件系统

[root@martin-host ~]# resize2fs /dev/cloud/docker 5G 
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/cloud/docker to 1310720 (4k) blocks.
The filesystem on /dev/cloud/docker is now 1310720 blocks long.

• 缩减逻辑卷的物理大小

[root@martin-host ~]# lvreduce -L 5G /dev/cloud/docker WARNING: Reducing active logical volume to 5.00 GiB.THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce cloud/docker? [y/n]: ySize of logical volume cloud/docker changed from 20.00 GiB (5120 extents) to 5.00 GiB (1280 extents).Logical volume cloud/docker successfully resized.

• 重新挂载，验证数据

[root@martin-host ~]# mount /dev/cloud/docker /cloud/docker/
[root@martin-host ~]# 
[root@martin-host ~]# ls /cloud/docker/
file01  file010  file02  file03  file04  file05  file06  file07  file08  file09  lost+found
[root@martin-host ~]# 
[root@martin-host ~]# lvscan ACTIVE            '/dev/cloud/openstack' [20.00 GiB] inheritACTIVE            '/dev/cloud/docker' [5.00 GiB] inheritACTIVE            '/dev/centos/swap' [1.00 GiB] inheritACTIVE            '/dev/centos/root' [18.21 GiB] inherit
[root@martin-host ~]# 
[root@martin-host ~]# df -hT | grep docker
/dev/mapper/cloud-docker    ext4      4.8G   33M  4.6G    1% /cloud/docker
[root@martin-host ~]# 

4、删除逻辑卷

• 卸载设备
• 删除fstab文件中的挂载条目
• 删除逻辑卷

[root@martin-host ~]# lvremove /dev/cloud/openstack 
Do you really want to remove active logical volume cloud/openstack? [y/n]: yLogical volume "openstack" successfully removed