16次课（ lvm讲解、磁盘故障小案例）

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ahanshuo 2018-01-03 00:04:38 ©著作权

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4.10/4.11/4.12 lvm讲解

lvm很方便的去扩容或缩容磁盘空间，但是一旦出现了问题，比如说磁盘由于使用lvm有一天文件系统发生了损坏然后数据找不到了，要去恢复数据的时候肯定想下首先硬盘划分了物理分区，然后在物理分区的基础上又划分了lvm，lvm是一个很复杂的结构，所以恢复起来会一定的麻烦，毕竟这个lvm是一个软件，他有一定的风险。

先安装lvm #yum install -y lvm2

看步骤图如下：

怎么做这些操作如下所示 1 准备磁盘分区 2 创建三个分区，分别1G 3 改变分区类型为lvm
示例如下

准备完磁盘分区后创建物理卷创建物理卷命令用pvcreate pvreate /dev/sdb1 pvreate /dev/sdb2 pvreate /dev/sdb3

示例如下

pvs也可以查看物理卷

创建物理卷之后创建卷组如下所示

vgremove删除卷组

有了卷组后就创建逻辑卷示例如下

格式化完成后挂载

以上做完后再mnt下创建一个目录 touch一个文件写入一串数字echo

下面做一个扩容逻辑卷操作，逻辑卷存在的价值在于能够方便的去扩容和缩容当然缩容用的少，大多数用的扩容，

缩减逻辑卷

[root@hanshuo-10 ~]# umount /mnt/           /先卸载mnt
[root@hanshuo-10 ~]# e2fsck -f  /dev/vg1/lv1    //检查磁盘错误
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/vg1/lv1: 13/49400 files (7.7% non-contiguous), 11886/204800 blocks
[root@hanshuo-10 ~]# resize2fs  /dev/vg1/lv1 100M         //更新逻辑卷信息
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/vg1/lv1 to 102400 (1k) blocks.
The filesystem on /dev/vg1/lv1 is now 102400 blocks long.

[root@hanshuo-10 ~]# lvresize -L 100M /dev/vg1/lv1         //重分大小
  WARNING: Not using lvmetad because duplicate PVs were found.
  WARNING: Use multipath or vgimportclone to resolve duplicate PVs?
  WARNING: After duplicates are resolved, run "pvscan --cache" to enable lvmetad.
  WARNING: Reducing active logical volume to 100.00 MiB.
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce vg1/lv1? [y/n]: y
  Size of logical volume vg1/lv1 changed from 200.00 MiB (50 extents) to 100.00 MiB (25 extents).
  Logical volume vg1/lv1 successfully resized.
[root@hanshuo-10 ~]# lvdisplay
  WARNING: Not using lvmetad because duplicate PVs were found.
  WARNING: Use multipath or vgimportclone to resolve duplicate PVs?
  WARNING: After duplicates are resolved, run "pvscan --cache" to enable lvmetad.
  --- Logical volume ---
  LV Path                /dev/vg1/lv1
  LV Name                lv1
  VG Name                vg1
  LV UUID                Pcl7nl-a26S-MszK-rL07-Qzod-N44X-GHdxip
  LV Write Access        read/write
  LV Creation host, time hanshuo-10, 2018-01-02 22:55:48 +0800
  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           253:0
   
[root@hanshuo-10 ~]# !mount
mount /dev/vg1/lv1 /mnt/
[root@hanshuo-10 ~]# la /mnr
bash: la: 未找到命令...
[root@hanshuo-10 ~]# ls /mnt/
1212  23.txt  lost+found

扩容卷组 /dev/sdb3没有用要把sdb3加到卷组里边去

[root@hanshuo-10 ~]# pvcreate /dev/sdb3 WARNING: Not using lvmetad because duplicate PVs were found. WARNING: Use multipath or vgimportclone to resolve duplicate PVs? WARNING: After duplicates are resolved, run "pvscan --cache" to enable lvmetad. Physical volume "/dev/sdb3" successfully created. [root@hanshuo-10 ~]# vgextend vg1 /dev/sdb3 WARNING: Not using lvmetad because duplicate PVs were found. WARNING: Use multipath or vgimportclone to resolve duplicate PVs? WARNING: After duplicates are resolved, run "pvscan --cache" to enable lvmetad. Volume group "vg1" successfully extended [root@hanshuo-10 ~]# vgdisplay WARNING: Not using lvmetad because duplicate PVs were found. WARNING: Use multipath or vgimportclone to resolve duplicate PVs? WARNING: After duplicates are resolved, run "pvscan --cache" to enable lvmetad. --- Volume group --- VG Name vg1 System ID
Format lvm2 Metadata Areas 3 Metadata Sequence No 6 VG Access read/write VG Status resizable MAX LV 0 Cur LV 1 Open LV 1 Max PV 0 Cur PV 3 Act PV 3 VG Size <2.99 GiB PE Size 4.00 MiB Total PE 765 Alloc PE / Size 75 / 300.00 MiB Free PE / Size 690 / <2.70 GiB VG UUID UWgQjw-pOGA-zCfw-9ZnY-8dCX-mckZ-hK7Fg3

[root@hanshuo-10 ~]# vgs WARNING: Not using lvmetad because duplicate PVs were found. WARNING: Use multipath or vgimportclone to resolve duplicate PVs? WARNING: After duplicates are resolved, run "pvscan --cache" to enable lvmetad. VG #PV #LV #SN Attr VSize VFree vg1 3 1 0 wz--n- <2.99g <2.70g [root@hanshuo-10 ~]# lvresize -L 300M /dev/vg1/lv1 WARNING: Not using lvmetad because duplicate PVs were found. WARNING: Use multipath or vgimportclone to resolve duplicate PVs? WARNING: After duplicates are resolved, run "pvscan --cache" to enable lvmetad. New size (75 extents) matches existing size (75 extents). [root@hanshuo-10 ~]# lvresize -L 240M /dev/vg1/lv1 WARNING: Not using lvmetad because duplicate PVs were found. WARNING: Use multipath or vgimportclone to resolve duplicate PVs? WARNING: After duplicates are resolved, run "pvscan --cache" to enable lvmetad. WARNING: Reducing active and open logical volume to 240.00 MiB. THIS MAY DESTROY YOUR DATA (filesystem etc.) Do you really want to reduce vg1/lv1? [y/n]: y Size of logical volume vg1/lv1 changed from 300.00 MiB (75 extents) to 240.00 MiB (60 extents). Logical volume vg1/lv1 successfully resized. [root@hanshuo-10 ~]# dh -f bash: dh: 未找到命令... [root@hanshuo-10 ~]# df -h 文件系统容量已用可用已用% 挂载点 /dev/sda3 36G 5.3G 31G 15% / devtmpfs 907M 0 907M 0% /dev tmpfs 916M 0 916M 0% /dev/shm tmpfs 916M 8.9M 907M 1% /run tmpfs 916M 0 916M 0% /sys/fs/cgroup /dev/sda1 497M 124M 373M 25% /boot tmpfs 184M 0 184M 0% /run/user/0 /dev/mapper/vg1-lv1 97M 5.2M 92M 6% /mnt