lvm的扩展与缩减

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这篇文章主要介绍lv在容量不足的情况下如何实现在线扩展或缩减。

注意:对于ext系列文件系统,可扩展可缩减(但缩减需要先取消挂载);
而对于xfs系列文件系统,仅仅可以扩展;

当然,lv的扩展需要vg有足够的空间,否则,只能先打pv的主意了,把vg先进行扩展;如下所示

[email protected] ~ ]#vgdisplay 
  --- Volume group ---
  VG Name               vg0
  System ID             
  Format                lvm2
  Metadata Areas        4
  Metadata Sequence No  3
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               1
  Max PV                0
  Cur PV                4
  Act PV                4
  VG Size               <5.94 GiB
  PE Size               16.00 MiB
  Total PE              380
  Alloc PE / Size       380 / <5.94 GiB
  Free  PE / Size       0 / 0   
  VG UUID               0PV32k-u0PM-0wh5-VyWR-A5qD-ERXa-2VPEiJ

创建pv

[[email protected] ~ ]#lsblk
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda           8:0    0  200G  0 disk 
├─sda1        8:1    0    1G  0 part /boot
├─sda2        8:2    0   50G  0 part /
├─sda3        8:3    0   30G  0 part /data
├─sda4        8:4    0    1K  0 part 
└─sda5        8:5    0    3G  0 part [SWAP]
sdb           8:16   0   20G  0 disk 
├─sdb1        8:17   0    1G  0 part 
│ └─vg0-lv1 253:1    0  4.5G  0 lvm  
└─sdb2        8:18   0    2G  0 part 
  ├─vg0-lv0 253:0    0  1.5G  0 lvm  /root/test1
  └─vg0-lv1 253:1    0  4.5G  0 lvm  
sdc           8:32   0   20G  0 disk 
├─sdc1        8:33   0    1G  0 part 
│ └─vg0-lv1 253:1    0  4.5G  0 lvm  
└─sdc2        8:34   0    2G  0 part 
  └─vg0-lv1 253:1    0  4.5G  0 lvm  
sdd           8:48   0   20G  0 disk 
sde           8:64   0   20G  0 disk 
sr0          11:0    1  8.8G  0 rom  

以/dev/sdd和/dev/sde为例,进行创建

[[email protected] ~ ]#pvcreate /dev/sd{d,e}
  Physical volume "/dev/sdd" successfully created.
  Physical volume "/dev/sde" successfully created.

查看pv信息,很明显,没有vg归属的就是刚刚创建的pv

[[email protected] ~ ]#pvs
  PV         VG  Fmt  Attr PSize    PFree 
  /dev/sdb1  vg0 lvm2 a--  1008.00m     0 
  /dev/sdb2  vg0 lvm2 a--     1.98g     0 
  /dev/sdc1  vg0 lvm2 a--  1008.00m     0 
  /dev/sdc2  vg0 lvm2 a--     1.98g     0 
  /dev/sdd       lvm2 ---    20.00g 20.00g
  /dev/sde       lvm2 ---    20.00g 20.00g

扩展vg

未扩展之前:

[[email protected] ~ ]#vgdisplay 
  --- Volume group ---
  VG Name               vg0
  System ID             
  Format                lvm2
  Metadata Areas        4
  Metadata Sequence No  3
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               1
  Max PV                0
  Cur PV                4
  Act PV                4   
  VG Size               <5.94 GiB                               ## 大小6G
  PE Size               16.00 MiB
  Total PE              380                                     ## 总数量380
  Alloc PE / Size       380 / <5.94 GiB
  Free  PE / Size       0 / 0                                   ## 空闲为0
  VG UUID               0PV32k-u0PM-0wh5-VyWR-A5qD-ERXa-2VPEiJ

开搞:vgextend vgName pvName [pvName....]

[[email protected] ~ ]#vgextend vg0 /dev/sd{d,e}
  Volume group "vg0" successfully extended

查看扩展后的vg信息

[[email protected] ~ ]#vgs
  VG  #PV #LV #SN Attr   VSize   VFree  
  vg0   6   2   0 wz--n- <45.91g <39.97g
[[email protected] ~ ]#vgdisplay 
  --- Volume group ---
  VG Name               vg0
  System ID             
  Format                lvm2
  Metadata Areas        6
  Metadata Sequence No  4
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               1
  Max PV                0
  Cur PV                6
  Act PV                6
  VG Size               <45.91 GiB                              ## 增加40G
  PE Size               16.00 MiB
  Total PE              2938
  Alloc PE / Size       380 / <5.94 GiB
  Free  PE / Size       2558 / <39.97 GiB                       ## 空闲为2558
  VG UUID               0PV32k-u0PM-0wh5-VyWR-A5qD-ERXa-2VPEiJ

缩减vg

开搞:vgreduce vgName pvName [pvName....]

[[email protected] ~ ]#vgreduce vg0 /dev/sdd
  Removed "/dev/sdd" from volume group "vg0"

查看vg是否缩减:

[[email protected] ~ ]#vgs
  VG  #PV #LV #SN Attr   VSize  VFree 
  vg0   5   2   0 wz--n- 25.92g 19.98g
[[email protected] ~ ]#vgdisplay 
  --- Volume group ---
  VG Name               vg0
  System ID             
  Format                lvm2
  Metadata Areas        5
  Metadata Sequence No  5
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               1
  Max PV                0
  Cur PV                5
  Act PV                5
  VG Size               25.92 GiB                                   ## 大小由46G缩为26G
  PE Size               16.00 MiB
  Total PE              1659
  Alloc PE / Size       380 / <5.94 GiB
  Free  PE / Size       1279 / 19.98 GiB                            ## 空闲PE数量减少
  VG UUID               0PV32k-u0PM-0wh5-VyWR-A5qD-ERXa-2VPEiJ

扩展lv

未扩展之前的信息:

[[email protected] ~ ]#lvdisplay 
  --- Logical volume ---
  LV Path                /dev/vg0/lv0
  LV Name                lv0
  VG Name                vg0
  LV UUID                HFNlrP-1da7-rdiJ-Jqew-0ym5-Lx0H-twQup5
  LV Write Access        read/write
  LV Creation host, time centos7.localdomain, 2018-08-15 16:31:01 +0800
  LV Status              available
  # open                 1
  LV Size                <1.47 GiB
  Current LE             94
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:0

  --- Logical volume ---
  LV Path                /dev/vg0/lv1
  LV Name                lv1
  VG Name                vg0
  LV UUID                L1RYsF-rNHs-y8xE-9ao1-WYci-CRIR-X5hkf4
  LV Write Access        read/write
  LV Creation host, time centos7.localdomain, 2018-08-15 16:52:41 +0800
  LV Status              available
  # open                 0
  LV Size                <4.47 GiB
  Current LE             286
  Segments               4
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:1

开搞:lvextend -L [+][mMgGtT] /dev/vgName/lvName

上面的意思就是说可以直接-L指定扩展后的大小;或者-L +增加的大小都可以

## 给lv0增加10G
[[email protected] ~ ]#lvextend -L +10G /dev/vg0/lv0
  Size of logical volume vg0/lv0 changed from <1.47 GiB (94 extents) to <11.47 GiB (734 extents).
  Logical volume vg0/lv0 successfully resized.

查看扩展后的lv0

[[email protected] ~ ]#lvdisplay /dev/vg0/lv0
  --- Logical volume ---
  LV Path                /dev/vg0/lv0
  LV Name                lv0
  VG Name                vg0
  LV UUID                HFNlrP-1da7-rdiJ-Jqew-0ym5-Lx0H-twQup5
  LV Write Access        read/write
  LV Creation host, time centos7.localdomain, 2018-08-15 16:31:01 +0800
  LV Status              available
  open                 1
  LV Size                <11.47 GiB                         ## 瞬间增加10G
  Current LE             734
  Segments               2
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:0

df查看一下文件系统容量是否增加

[[email protected] ~ ]#df -h
Filesystem           Size  Used Avail Use% Mounted on
/dev/sda2             50G  3.8G   47G   8% /
devtmpfs             599M     0  599M   0% /dev
tmpfs                615M     0  615M   0% /dev/shm
tmpfs                615M   18M  597M   3% /run
tmpfs                615M     0  615M   0% /sys/fs/cgroup
/dev/sda3             30G 1012M   29G   4% /data
/dev/sda1           1014M  155M  860M  16% /boot
tmpfs                123M   12K  123M   1% /run/user/42
tmpfs                123M     0  123M   0% /run/user/0
/dev/mapper/vg0-lv0  1.5G  4.5M  1.4G   1% /root/test1              ## 发现没有变化

使用resize2fs在线扩展ext系列文件系统(注意 :resize2fs仅仅适用于ext系列文件系统,对于xfs需要用xfs_growfs命令,并且命令后跟挂载点,而不是设备名)

[[email protected] ~ ]#resize2fs /dev/vg0/lv0
resize2fs 1.42.9 (28-Dec-2013)
Filesystem at /dev/vg0/lv0 is mounted on /root/test1; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 2
The filesystem on /dev/vg0/lv0 is now 3006464 blocks long.

[[email protected] ~ ]#df -h
Filesystem           Size  Used Avail Use% Mounted on
/dev/sda2             50G  3.8G   47G   8% /
devtmpfs             599M     0  599M   0% /dev
tmpfs                615M     0  615M   0% /dev/shm
tmpfs                615M   18M  597M   3% /run
tmpfs                615M     0  615M   0% /sys/fs/cgroup
/dev/sda3             30G 1012M   29G   4% /data
/dev/sda1           1014M  155M  860M  16% /boot
tmpfs                123M   12K  123M   1% /run/user/42
tmpfs                123M     0  123M   0% /run/user/0
/dev/mapper/vg0-lv0   12G  7.3M   11G   1% /root/test1              ## 同步成功

先扩展lv,再扩展文件系统,感觉好麻烦,可以在命令后面加参数-r或--resizefs,实现一步更新,并且支持xfs文件系统

[[email protected] ~ ]#lvextend -r  -L +5G /dev/vg0/lv1 
  Size of logical volume vg0/lv1 changed from <4.47 GiB (286 extents) to <9.47 GiB (606 extents).
  Logical volume vg0/lv1 successfully resized.
meta-data=/dev/mapper/vg0-lv1    isize=512    agcount=4, agsize=292864 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0 spinodes=0
data     =                       bsize=4096   blocks=1171456, 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 1171456 to 2482176

缩减lv——-仅支持ext系列

一般情况下不会缩减,因为有可能造成数据损坏,建议先备份数据

步骤1:先取消卸载;
[[email protected] ~ ]#umount test1

步骤2:检查文件系统;
[[email protected] ~ ]#fsck -f /dev/vg0/lv0
fsck from util-linux 2.23.2
e2fsck 1.42.9 (28-Dec-2013)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/mapper/vg0-lv0: 11/417664 files (9.1% non-contiguous), 36107/1695744 blocks

步骤3:缩减文件系统;
[[email protected] ~ ]#resize2fs /dev/vg0/lv0 5G
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/vg0/lv0 to 1310720 (4k) blocks.
The filesystem on /dev/vg0/lv0 is now 1310720 blocks long.

步骤4:缩减逻辑卷,有可能损坏数据,强烈建议备份
 格式:lvreduce -L [-][mMgGtT] /dev/vgName/lvName
[[email protected] ~ ]#lvreduce -L 2G /dev/vg0/lv0
  WARNING: Reducing active logical volume to 2.00 GiB.
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce vg0/lv0? [y/n]: y
  Size of logical volume vg0/lv0 changed from <6.47 GiB (414 extents) to 2.00 GiB (128 extents).
  Logical volume vg0/lv0 successfully resized.

步骤5:验证
[[email protected] ~ ]#lvdisplay /dev/vg0/lv0
  --- Logical volume ---
  LV Path                /dev/vg0/lv0
  LV Name                lv0
  VG Name                vg0
  LV UUID                HFNlrP-1da7-rdiJ-Jqew-0ym5-Lx0H-twQup5
  LV Write Access        read/write
  LV Creation host, time centos7.localdomain, 2018-08-15 16:31:01 +0800
  LV Status              available
   open                 0
  LV Size                2.00 GiB
  Current LE             128
  Segments               2
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:0

修改lv名和vg名

修改lv

格式:lvrename oldname newname

[[email protected] ~ ]#lvrename /dev/vg0/lv0 /dev/vg0/xin
  Renamed "lv0" to "xin" in volume group "vg0"

[[email protected] ~ ]#lvdisplay /dev/vg0/xin
  --- Logical volume ---
  LV Path                /dev/vg0/xin
  LV Name                xin
  VG Name                vg0
  LV UUID                HFNlrP-1da7-rdiJ-Jqew-0ym5-Lx0H-twQup5
  LV Write Access        read/write
  LV Creation host, time centos7.localdomain, 2018-08-15 16:31:01 +0800
  LV Status              available
  # open                 1
  LV Size                <6.47 GiB
  Current LE             414
  Segments               2
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:0

修改vg

格式:vgrename oldname newname

[[email protected] ~ ]#vgrename vg0 VG0
  Volume group "vg0" successfully renamed to "VG0"

[[email protected] ~ ]#vgdisplay VG0
  --- Volume group ---
  VG Name               VG0
  System ID             
  Format                lvm2
  Metadata Areas        5
  Metadata Sequence No  10
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               2
  Max PV                0
  Cur PV                5
  Act PV                5
  VG Size               25.92 GiB
  PE Size               16.00 MiB
  Total PE              1659
  Alloc PE / Size       1020 / <15.94 GiB
  Free  PE / Size       639 / 9.98 GiB
  VG UUID               0PV32k-u0PM-0wh5-VyWR-A5qD-ERXa-2VPEiJ

删除pv、vg、lv

[[email protected] ~ ]#lvremove /dev/vg0/lv0

[[email protected] ~ ]#vgremove vg0
Do you really want to remove volume group "vg0" containing 1 logical volumes? [y/n]: y
Volume group "vg0" successfully removed

[[email protected] ~ ]#pvremove /dev/sde
  Labels on physical volume "/dev/sde" successfully wiped

总结:

扩展逻辑卷

1. 查看vg空间是否充裕,如果充裕,直接扩展;否则先扩展vg
vgdisplay

2. 扩展lv并同步文件系统

lvextend -l +100%FREE  /dev/vg0/lv0 
    ext系列: resize2fs /dev/vg0/lv0  
    xfs系列: xfs_grow  /mnt/lv0
或者一条命令搞定:
lvextend  -r -l +100%FREE  /dev/vg0/lv0

3.df -h 查看是否同步

缩减逻辑卷:

1.先取消挂载
umount /mnt/lv0 

2.检查文件系统
fsck -f /dev/vg0/lv0

3.缩减文件系统
resize2fs /dev/vg0/lv0  1G

4.缩减逻辑卷
lvreduce -L 1G  /dev/vg0/lv0  (注意:缩减的大小和文件系统对应)

5.mount挂载使用

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