LVM

1.lvm管理设备，使设备的大小根据需要变化
pv:物理卷
pe:物理拓展分区
vg:物理卷组
lvm:逻辑卷

2.lvm的建立
（1）

划分物理分区，并修改分区标签为1vm（lvm类型id为8e）

pvcreate /dev/vdb1             ## 创建物理卷vgcreate vg0 /dev/vdb1         ##创建物理卷组lvcreate -L 100M -n lv0 vg0    ##创建逻辑卷mkfs.xfs /dev/vg0/lv0          ##格式化设备mount /dev/vg0/lv0  /westos    ##设备挂载投入使用

[root@localhost ~]# pvcreate /dev/vdb1  Physical volume "/dev/vdb1" successfully created[root@localhost ~]# mkdir /westos[root@localhost ~]# chmod 777 /westos[root@localhost ~]# ls -ld /westosdrwxrwxrwx. 2 root root 6 Nov  4 21:47 /westos[root@localhost ~]#[root@localhost ~]# vgcreate vg0 /dev/vdb1  Volume group "vg0" successfully created[root@localhost ~]# lvcreate -L 100M -n lv0 vg0  Logical volume "lv0" created[root@localhost ~]# mkfs.xfs /dev/vg0/lv0meta-data=/dev/vg0/lv0           isize=256    agcount=4, agsize=6400 blks         =                       sectsz=512   attr=2, projid32bit=1         =                       crc=0data     =                       bsize=4096   blocks=25600, imaxpct=25         =                       sunit=0      swidth=0 blksnaming   =version 2              bsize=4096   ascii-ci=0 ftype=0log      =internal log           bsize=4096   blocks=853, version=2         =                       sectsz=512   sunit=0 blks, lazy-count=1realtime =none                   extsz=4096   blocks=0, rtextents=0[root@localhost ~]# mount /dev/vg0/lv0 /westos

监控：watch -n 1 ‘pvs;echo +++++++;vgs;echo ++++++;lvs;echo ======;df -h /westos’

Every 1.0s: pvs;echo +++++++;vgs;echo ++++++;lvs;echo ======;df -h ...  Sat Nov  4 22:10:56 2017  PV         VG   Fmt  Attr PSize   PFree  /dev/vdb1  vg0  lvm2 a--  496.00m      0  /dev/vdb2  vg0  lvm2 a--  496.00m 292.00m+++++++  VG   #PV #LV #SN Attr   VSize   VFree  vg0    2   1   0 wz--n- 992.00m 292.00m++++++  LV   VG   Attr       LSize   Pool Origin Data%  Move Log Cpy%Sync Convert##### lv0  vg0  -wi-ao---- 700.00m======Filesystem           Size  Used Avail Use% Mounted on/dev/mapper/vg0-lv0  697M  6.0M  691M   1% /westos

(2)

pvcreate  /dev/vdb1                   vgcreate -s 4M westos /dev/vdb1         ##生成一个物理拓展分区大小为4M，物理卷组westos为4Mlvcreate -l 50  -n lv0 westos           ##逻辑卷组为200M

3.lvm的拉深
当vg中剩余容量充足的时候

lvextend -L 400M /dev/vg0/lv0    ##将设备从100M拉深为400Mxfs_growfs /dev/vg0/lv0          ##将文件系统拉深

[root@localhost ~]# lvextend -L 400M /dev/vg0/lv0  Extending logical volume lv0 to 400.00 MiB  Logical volume lv0 successfully resized[root@localhost ~]# xfs_growfs /dev/vg0/lv0meta-data=/dev/mapper/vg0-lv0    isize=256    agcount=4, agsize=6400 blks         =                       sectsz=512   attr=2, projid32bit=1         =                       crc=0data     =                       bsize=4096   blocks=25600, imaxpct=25         =                       sunit=0      swidth=0 blksnaming   =version 2              bsize=4096   ascii-ci=0 ftype=0log      =internal               bsize=4096   blocks=853, version=2         =                       sectsz=512   sunit=0 blks, lazy-count=1realtime =none                   extsz=4096   blocks=0, rtextents=0data blocks changed from 25600 to 102400

当vg中剩余容量不足的时候
新建分区/dev/vdb2，改标签为lvm

pvcreate /dev/vdb2                 ##将/dev/vdb2添加到pv中vgextend vg0 /dev/vdb2             ##将/dev/vdb2添加到vg0中lvextend -L 700M /dev/vg0/lv0      ##将/dev/vg0/lv0设备拉深到700Mxfs_growfs /dev/vg0/lv0            ##拉深文件系统[root@localhost ~]# pvcreate /dev/vdb2  Physical volume "/dev/vdb2" successfully created[root@localhost ~]# vgectend  vg0 /dev/vdb2bash: vgectend: command not found...[root@localhost ~]# vgextend  vg0 /dev/vdb2  Volume group "vg0" successfully extended[root@localhost ~]# lvextend -L 700M /dev/vg0/lv0  Extending logical volume lv0 to 700.00 MiB  Logical volume lv0 successfully resized[root@localhost ~]# xfs_growfs /dev/vg0/lv0meta-data=/dev/mapper/vg0-lv0    isize=256    agcount=16, agsize=6400 blks         =                       sectsz=512   attr=2, projid32bit=1         =                       crc=0data     =                       bsize=4096   blocks=102400, imaxpct=25         =                       sunit=0      swidth=0 blksnaming   =version 2              bsize=4096   ascii-ci=0 ftype=0log      =internal               bsize=4096   blocks=853, version=2         =                       sectsz=512   sunit=0 blks, lazy-count=1realtime =none                   extsz=4096   blocks=0, rtextents=0data blocks changed from 102400 to 179200[root@localhost ~]#

注意：扩容的极限为18EB-1TB

4.在ext4文件系统中：

umount  /dev/vg0/lv0     ##卸载设备mkfs.ext4  /dev/vg0/lv0  ##格式化设备为ext4mke2fs 1.42.9 (28-Dec-2013)Filesystem label=OS type: LinuxBlock size=4096 (log=2)Fragment size=4096 (log=2)Stride=0 blocks, Stripe width=0 blocks44832 inodes, 179200 blocks8960 blocks (5.00%) reserved for the super userFirst data block=0Maximum filesystem blocks=1845493766 block groups32768 blocks per group, 32768 fragments per group7472 inodes per groupSuperblock backups stored on blocks:        32768, 98304, 163840Allocating group tables: doneWriting inode tables: doneCreating journal (4096 blocks): doneWriting superblocks and filesystem accounting information: done

拉深

lvextend -L 400M /dev/vg0/lv0       ##将设备拉深到700Mresize2fs /dev/vg0/lv0                    ##拉深文件系统

缩减

umount  /dev/vg0/lv0             ##卸载设备e2fsck -f /dev/vg0/lv0           ##扫描设备上的数据,查看文件的大小,根据文件的大小缩减设备。e2fsck 1.42.9 (28-Dec-2013)Pass 1: Checking inodes, blocks, and sizesPass 2: Checking directory structurePass 3: Checking directory connectivityPass 4: Checking reference countsPass 5: Checking group summary information/dev/vg0/lv0: 11/44832 files (0.0% non-contiguous), 7272/179200 blocksresize2fs /dev/vg0/lv0 200M       ##缩减文件系统resize2fs 1.42.9 (28-Dec-2013)Resizing the filesystem on /dev/vg0/lv0 to 51200 (4k) blocks.The filesystem on /dev/vg0/lv0 is now 51200 blocks long.

mount /dev/vg0/lv0  /westos/    ##挂载设备lvreduce -L 200M /dev/vg0/lv0   ##缩减设备WARNING: Reducing active and open logical volume to 200.00 MiB THIS MAY DESTROY YOUR DATA (filesystem etc.)Do you really want to reduce lv0? [y/n]: y  Reducing logical volume lv0 to 200.00 MiB  Logical volume lv0 successfully resized[root@localhost ~]# lvextend -L 400M /dev/vg0/lv0  Extending logical volume lv0 to 400.00 MiB  Logical volume lv0 successfully resized

5.对卷组

pvmove /dev/vdb1  /dev/vdb2  ##当要移除的分区存在数据时，需要把数据迁移到其他的pv中vgreduce vg0 /dev/vdb1       ##移除卷组中的/dev/vdb1pvremove /dev/vdb1           ##将/dev/vdb1从物理卷中移除

[root@localhost ~]# pvmove /dev/vdb1  /dev/vdb2  /dev/vdb1: Moved: 100.0%[root@localhost ~]# vgreduce vg0 /dev/vdb1  Removed "/dev/vdb1" from volume group "vg0"[root@localhost ~]# pvremove /dev/vdb1  Labels on physical volume "/dev/vdb1" successfully wiped[root@localhost ~]#

6.lvm快照
lvm快照： ##读取数据读取的是设备

lvcreate -L 100M -n lv0backup  -s /dev/vg0/lv0     ##对/dev/vg0/lv0进行快照，快照的大小为100M，生成的快照文件为v0backup。mount /dev/vg0/lv0backup /westos/     ##挂载生成的快照[root@localhost ~]# lvcreate -L 80M -n lv0backup  -s /dev/vg0/lv0  Logical volume "lv0backup" created[root@localhost ~]# mount /dev/vg0/lv0backup /westos/[root@localhost ~]#

7.lvm的删除

umount /dev/vg0/lv0backup         ##卸载快照lvremove /dev/vg0/lv0backup       ##移除快照lvremove /dev/vg0/lv0             ##移除逻辑卷              vgremove vg0                      ##移除物理卷组pvremove /dev/vdb2                ##将/dev/dvb2从物理卷中移除

fdisk /dev/vdb

[root@localhost ~]# umount /dev/vg0/lv0backupumount: /dev/vg0/lv0backup: not mounted[root@localhost ~]# lvremove /dev/vg0/lv0backupDo you really want to remove active logical volume lv0backup? [y/n]: y  Logical volume "lv0backup" successfully removed[root@localhost ~]# lvremove /dev/vg0/lv0Do you really want to remove active logical volume lv0? [y/n]: y  Logical volume "lv0" successfully removed[root@localhost ~]# vgremove vg0  Volume group "vg0" successfully removed[root@localhost ~]# pvremove /dev/vdb2  Labels on physical volume "/dev/vdb2" successfully wiped[root@localhost ~]# fdisk /dev/vdbWelcome to fdisk (util-linux 2.23.2).Changes will remain in memory only, until you decide to write them.Be careful before using the write command.Command (m for help): dPartition number (1-3, default 3): 1Partition 1 is deletedCommand (m for help): dPartition number (2,3, default 3):Partition 3 is deletedCommand (m for help): dSelected partition 2Partition 2 is deletedCommand (m for help): pDisk /dev/vdb: 10.7 GB, 10737418240 bytes, 20971520 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk label type: dosDisk identifier: 0xe503464f   Device Boot      Start         End      Blocks   Id  SystemCommand (m for help): wq

当误删除（即直接使用fdisk /dev/vdb删除/dev/vdb1），出现removemissing时，处理方法为：
vgreduce vgo –removemissing –force