LVM逻辑卷管理测试——逻辑卷扩展、收缩、快照及删除

一、逻辑卷扩展

[root@lxjtest /]# umount /testLVM/
[root@lxjtest /]# df -h
Filesystem             Size  Used Avail Use% Mounted on
/dev/mapper/rhel-root  3.7G  896M  2.9G  24% /
devtmpfs               910M     0  910M   0% /dev
tmpfs                  920M     0  920M   0% /dev/shm
tmpfs                  920M  8.4M  912M   1% /run
tmpfs                  920M     0  920M   0% /sys/fs/cgroup
/dev/sda1              297M  114M  184M  39% /boot
tmpfs                  184M     0  184M   0% /run/user/0
[root@lxjtest /]#

第1步：把上个试验中的逻辑卷fuck_lv1扩展至300MB

[root@lxjtest /]# lvdisplay testVG
  --- Logical volume ---
  LV Path                /dev/testVG/fuck_lv1
  LV Name                fuck_lv1
  VG Name                testVG
  LV UUID                RKzHdO-NX2i-Za40-kWNg-RIox-yi9j-z9251R
  LV Write Access        read/write
  LV Creation host, time lxjtest.rusky.com, 2017-08-07 23:35:10 -0400
  LV Status              available
  # open                 0
  LV Size                200.00 MiB
  Current LE             50
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:2
   
[root@lxjtest /]# lvs testVG
  LV       VG     Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  fuck_lv1 testVG -wi-a----- 200.00m                                                    
[root@lxjtest /]# lvextend -L 300M /dev/testVG/fuck_lv1 
  Size of logical volume testVG/fuck_lv1 changed from 200.00 MiB (50 extents) to 300.00 MiB (75 extents).
  Logical volume fuck_lv1 successfully resized.
[root@lxjtest /]# lvs testVG
  LV       VG     Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  fuck_lv1 testVG -wi-a----- 300.00m                                                    
[root@lxjtest /]#

第2步：检查磁盘容量，重置磁盘容量

[root@lxjtest /]# e2fsck -f /dev/testVG/fuck_lv1 
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/testVG/fuck_lv1: 12/51200 files (0.0% non-contiguous), 12116/204800 blocks
[root@lxjtest /]# resize2fs /dev/testVG/fuck_lv1 
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/testVG/fuck_lv1 to 307200 (1k) blocks.
The filesystem on /dev/testVG/fuck_lv1 is now 307200 blocks long.

第3步：重新挂载硬盘设备并查看挂载状态

[root@lxjtest /]# mount -a 
[root@lxjtest /]# df -h
Filesystem                   Size  Used Avail Use% Mounted on
/dev/mapper/rhel-root        3.7G  897M  2.9G  24% /
devtmpfs                     910M     0  910M   0% /dev
tmpfs                        920M     0  920M   0% /dev/shm
tmpfs                        920M  8.4M  912M   1% /run
tmpfs                        920M     0  920M   0% /sys/fs/cgroup
/dev/sda1                    297M  114M  184M  39% /boot
tmpfs                        184M     0  184M   0% /run/user/0
/dev/mapper/testVG-fuck_lv1  287M  2.1M  266M   1% /testLVM

二、逻辑卷收缩

缩小逻辑卷之前，先备份数据，然后检查文件系统完整性，再卸载文件系统，之后再来压缩。

[root@lxjtest /]# umount /testLVM/
[root@lxjtest /]# e2fsck -f /dev/testVG/fuck_lv1 
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/testVG/fuck_lv1: 12/77824 files (0.0% non-contiguous), 15988/307200 blocks
[root@lxjtest /]# resize2fs /dev/testVG/fuck_lv1 100M
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/testVG/fuck_lv1 to 102400 (1k) blocks.
The filesystem on /dev/testVG/fuck_lv1 is now 102400 blocks long.

[root@lxjtest /]# lvreduce -L 100M /dev/testVG/fuck_lv1 
  WARNING: Reducing active logical volume to 100.00 MiB
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce fuck_lv1? [y/n]: y
  Size of logical volume testVG/fuck_lv1 changed from 300.00 MiB (75 extents) to 100.00 MiB (25 extents).
  Logical volume fuck_lv1 successfully resized.
[root@lxjtest /]# lvs testVG
  LV       VG     Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  fuck_lv1 testVG -wi-a----- 100.00m                                                    
[root@lxjtest /]#

最后，重新挂载并查看文件系统：

[root@lxjtest /]# mount -a
[root@lxjtest /]# df -h
Filesystem                   Size  Used Avail Use% Mounted on
/dev/mapper/rhel-root        3.7G  896M  2.9G  24% /
devtmpfs                     910M     0  910M   0% /dev
tmpfs                        920M     0  920M   0% /dev/shm
tmpfs                        920M  8.4M  912M   1% /run
tmpfs                        920M     0  920M   0% /sys/fs/cgroup
/dev/sda1                    297M  114M  184M  39% /boot
tmpfs                        184M     0  184M   0% /run/user/0
/dev/mapper/testVG-fuck_lv1   93M  1.6M   85M   2% /testLVM

三、逻辑卷快照

LVM逻辑卷管理器还具备有“快照卷”的功能，这项功能很类似于虚拟机软件的还原时间点功能。例如可以对某一个LV逻辑卷设备做一次快照，如果今后发现数据被改错了，咱们可以把之前做好的快照卷进行覆盖还原，LVM逻辑卷管理器的快照功能有两项特点，第一是快照卷的大小应该尽量等同于LV逻辑卷的容量，第二是快照功能仅一次有效，一旦被还原后则会被自动立即删除，首先应当查看下卷组的信息：

[root@lxjtest testLVM]# ls -lht
total 46M
drwx------. 2 root root 12K Aug  7 23:51 lost+found
-rw-r--r--. 1 root root 46M Apr  5  2015 firefox-37.0.1.tar.bz2
[root@lxjtest testLVM]# df -h
Filesystem                   Size  Used Avail Use% Mounted on
/dev/mapper/rhel-root        3.7G  898M  2.9G  24% /
devtmpfs                     910M     0  910M   0% /dev
tmpfs                        920M     0  920M   0% /dev/shm
tmpfs                        920M  8.4M  912M   1% /run
tmpfs                        920M     0  920M   0% /sys/fs/cgroup
/dev/sda1                    297M  114M  184M  39% /boot
tmpfs                        184M     0  184M   0% /run/user/0
/dev/mapper/testVG-fuck_lv1   93M   48M   39M  55% /testLVM
/dev/sr0                     3.8G  3.8G     0 100% /mnt

在创建快照前，先在/testLVM中放入一些文件，以对比快照还原结果

[root@lxjtest testLVM]# pwd
/testLVM
[root@lxjtest testLVM]# ls -lht
total 46M
drwx------. 2 root root 12K Aug  7 23:51 lost+found
-rw-r--r--. 1 root root 46M Apr  5  2015 firefox-37.0.1.tar.bz2

第1步：使用-s参数来生成一个快照卷，使用-L参数来指定切割的大小，另外要记得在后面写上这个快照是针对那个LV逻辑卷设备做的。

[root@lxjtest testLVM]# lvcreate -L 100M -s -n SNAP /dev/testVG/fuck_lv1 
  Logical volume "SNAP" created.

  --- Logical volume ---
  LV Path                /dev/testVG/fuck_lv1
  LV Name                fuck_lv1
  VG Name                testVG
  LV UUID                RKzHdO-NX2i-Za40-kWNg-RIox-yi9j-z9251R
  LV Write Access        read/write
  LV Creation host, time lxjtest.rusky.com, 2017-08-07 23:35:10 -0400
  LV snapshot status     source of
                         SNAP [active]
  LV Status              available
  # open                 0
  LV Size                100.00 MiB
  Current LE             25
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:2
   
  --- Logical volume ---
  LV Path                /dev/testVG/SNAP
  LV Name                SNAP
  VG Name                testVG
  LV UUID                7eeuaw-FMmH-KA1o-45CG-0x4J-B3tK-AOJqFv
  LV Write Access        read/write
  LV Creation host, time lxjtest.rusky.com, 2017-08-08 04:20:52 -0400
  LV snapshot status     active destination for fuck_lv1
  LV Status              available
  # open                 0
  LV Size                100.00 MiB
  Current LE             25
  COW-table size         100.00 MiB
  COW-table LE           25
  Allocated to snapshot  0.09%
  Snapshot chunk size    4.00 KiB
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:5
  （略）

快照创建完成之后，删除之前在/testLVM中放入的文件。下面我们使用快照卷SNAP来还原之前的文件。

第2步：为了校验SNAP快照卷的效果，需要对逻辑卷进行快照合并还原操作，在这之前记得先卸载掉逻辑卷设备与目录的挂载~

[root@lxjtest /]# cd testLVM/
[root@lxjtest testLVM]#rm  firefox-37.0.1.tar.bz2 --删除原文件
[root@lxjtest testLVM]#touch testNewFile  --创建新文件
[root@lxjtest testLVM]# ls
lost+found  tesstNewFile
[root@lxjtest testLVM]# cd /
[root@lxjtest /]# umount /testLVM/  --卸载
[root@lxjtest /]# lvconvert --merge /dev/testVG/SNAP  --快照还原
  Merging of volume SNAP started.
  fuck_lv1: Merged: 99.9%
  fuck_lv1: Merged: 100.0%
[root@lxjtest /]# mount -a
[root@lxjtest /]# cd testLVM/
[root@lxjtest testLVM]# ls  --原文件已被还原出来。
firefox-37.0.1.tar.bz2  lost+found

lvconvert之后，快照卷/dev/testVG/SNAP会被自动删除掉，并且刚刚在逻辑卷设备被快照后再创建出来的100M垃圾文件也被清除了。

[root@lxjtest testLVM]# lvdisplay
  --- Logical volume ---
  LV Path                /dev/testVG/fuck_lv1
  LV Name                fuck_lv1
  VG Name                testVG
  LV UUID                RKzHdO-NX2i-Za40-kWNg-RIox-yi9j-z9251R
  LV Write Access        read/write
  LV Creation host, time lxjtest.rusky.com, 2017-08-07 23:35:10 -0400
  LV Status              available
  # open                 1
  LV Size                100.00 MiB
  Current LE             25
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:2
   （略）
[root@lxjtest testLVM]#

四、删除逻辑卷

当生产环境中想要重新部署或者不需要再继续使用LVM逻辑卷管理器了，除了提前备份好重要数据信息，还必须依次删除LV逻辑卷、VG卷组后再移除PV物理卷设备，这样的顺序不可颠倒。

第1步：取消逻辑卷与目录的挂载关联，删除配置文件中永久生效的设备参数。

[root@lxjtest ~]# umount /testLVM/
[root@lxjtest ~]# vi /etc/fstab 


#
# /etc/fstab
# Created by anaconda on Tue Aug  1 04:28:47 2017
#
# 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
#
/dev/mapper/rhel-root   /                       xfs     defaults        0 0
UUID=e7987771-c54c-4b36-8a5c-8e71f129c3fe /boot                   xfs     defaults        0 0
/dev/mapper/rhel-swap   swap                    swap    defaults        0 0
#/dev/testVG/fuck_lv1   /testLVM                ext4    defaults        0 0
#删除或注释该行

第2步：把LV逻辑卷设备删除，需要手工输入y来确认操作

[root@lxjtest ~]# lvdisplay
  --- Logical volume ---
  LV Path                /dev/testVG/fuck_lv1
  LV Name                fuck_lv1
  VG Name                testVG
  LV UUID                RKzHdO-NX2i-Za40-kWNg-RIox-yi9j-z9251R
  LV Write Access        read/write
  LV Creation host, time lxjtest.rusky.com, 2017-08-07 23:35:10 -0400
  LV Status              available
  # open                 0
  LV Size                100.00 MiB
  Current LE             25
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:2
   （略）
[root@lxjtest ~]# lvremove /dev/testVG/fuck_lv1 
Do you really want to remove active logical volume fuck_lv1? [y/n]: y
  Logical volume "fuck_lv1" successfully removed
[root@lxjtest ~]#

第3步：把VG卷组删除，此处只需写卷组名称即可，而无需设备完整绝对路径

[root@lxjtest ~]# vgdisplay  
  --- Volume group ---
  VG Name               testVG
  System ID             
  Format                lvm2
  Metadata Areas        2
  Metadata Sequence No  10
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                0
  Open LV               0
  Max PV                0
  Cur PV                2
  Act PV                2
  VG Size               3.99 GiB
  PE Size               4.00 MiB
  Total PE              1022
  Alloc PE / Size       0 / 0   
  Free  PE / Size       1022 / 3.99 GiB
  VG UUID               b3mykq-kcsp-Hdh4-rAos-vutt-ontI-6AWJ5K
 （略）
[root@lxjtest ~]# 
[root@lxjtest ~]# vgremove testVG
  Volume group "testVG" successfully removed
[root@lxjtest ~]#

第4步：把PV物理卷设备移除：

[root@lxjtest ~]# pvdisplay
  --- Physical volume ---
  PV Name               /dev/sda2
  VG Name               rhel
  PV Size               4.71 GiB / not usable 3.00 MiB
  Allocatable           yes (but full)
  PE Size               4.00 MiB
  Total PE              1204
  Free PE               0
  Allocated PE          1204
  PV UUID               V3kA1X-l7dr-03p4-HZcu-Ebj3-FRvb-r5vGMd
   
  "/dev/sdb" is a new physical volume of "2.00 GiB"
  --- NEW Physical volume ---
  PV Name               /dev/sdb
  VG Name               
  PV Size               2.00 GiB
  Allocatable           NO
  PE Size               0   
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               InfACr-fq1t-yi95-K1K3-dOHU-uezl-gfiPVa
   
  "/dev/sdc" is a new physical volume of "2.00 GiB"
  --- NEW Physical volume ---
  PV Name               /dev/sdc
  VG Name               
  PV Size               2.00 GiB
  Allocatable           NO
  PE Size               0   
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               aOtJga-uWop-ldnv-xIcj-TcLE-aq18-SrJO3p
   
[root@lxjtest ~]# pvremove /dev/sdb /dev/sdc
  Labels on physical volume "/dev/sdb" successfully wiped
  Labels on physical volume "/dev/sdc" successfully wiped
[root@lxjtest ~]#

可以再分别执行下lvdisplay、vgdisplay、pvdisplay命令来查看逻辑卷管理器信息，操作正确则会不能再看到我们创建的逻辑卷设备信息了。

posted on 2017-08-09 10:57 遠離塵世の方舟阅读(830) 评论(0) 编辑收藏举报

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