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 ~]# !mountmount /dev/vg1/lv1 /mnt/[root@hanshuo-10 ~]# la /mnrbash: 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/sdb3WARNING: 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 ~]# vgdisplayWARNING: 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 vg1System ID Format lvm2Metadata Areas 3Metadata Sequence No 6VG Access read/writeVG Status resizableMAX LV 0Cur LV 1Open LV 1Max PV 0Cur PV 3Act PV 3VG Size <2.99 GiBPE Size 4.00 MiBTotal PE 765Alloc PE / Size 75 / 300.00 MiBFree PE / Size 690 / <2.70 GiBVG 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/lv1WARNING: 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/lv1WARNING: 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]: ySize 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 -fbash: 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% /devtmpfs 916M 0 916M 0% /dev/shmtmpfs 916M 8.9M 907M 1% /runtmpfs 916M 0 916M 0% /sys/fs/cgroup/dev/sda1 497M 124M 373M 25% /boottmpfs 184M 0 184M 0% /run/user/0/dev/mapper/vg1-lv1 97M 5.2M 92M 6% /mnt