lvm study:

lvm名词：PV, PE, VG, LV   操作流程： 1、更改分区模式： #fdisk /dev/sda ============================================= Command (m for help): t Partition number (1-5): 5 Hex code (type L to list codes): 8e Changed system type of partition 5 to 8e (Linux LVM)   Command (m for help): p   Disk /dev/sda: 320.0 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes      Device Boot      Start         End      Blocks   Id  System /dev/sda1   *           1          33      265041   83  Linux /dev/sda2              34        2644    20972857+  83  Linux /dev/sda3            2645        3166     4192965   82  Linux swap / Solaris /dev/sda4            3167       38913   287137777+   5  Extended /dev/sda5            3167       38913   287137746   8e  Linux LVM   Command (m for help): w The partition table has been altered!   Calling ioctl() to re-read partition table.   WARNING: Re-reading the partition table failed with error 16: Device or resource busy. The kernel still uses the old table. The new table will be used at the next reboot. Syncing disks. ==================================================================== #partprobe   #PV操作阶段   #pvcreate /dev/sda5 Physical volume "/dev/sda5" successfully created  表示执行成功。 =================================================== 此处报错：Can't open /dev/sda5 exclusively. Mounted filesystem? 解决如下： #df -h 查找dev/sda5挂载的分区，卸载掉。 #umount /dev/sda5 执行完检查没有挂载后，重新执行上面的命令。 =================================================================== #pvscan #pvdisplay     VG操作阶段   #vgcreate -s 16M vgdisk /dev/sda5  创建一个名位vgdisk的VG，且制定pe为16M #vgscan #vgdisplay     增加VG的容量命令：   vgextend vgdisk /dev/sda6   (这里是假设还有个sda6的pv)   =====================================================================   LV阶段：   #lvcreate -l 7000 -n lvdisk vgdisk  创建一个7000个PE的名称为lvdisk的LV # ll /dev/vgdisk/lvdisk  lrwxrwxrwx 1 root root 29 Dec  7 11:01 /dev/vgdisk/lvdisk -> /dev/mapper/vgdisk-lvdisk #lvdisplay     Block device           253:0   #档案系统阶段： #mkfs.ext3.html' target='_blank'>mkfs.ext3 /dev/vgdisk/lvdisk #mount /dev/vgdisk/lvdisk /data   这样LV就挂载上了，我们可以做任何操作了。。   ========================================================================= 下面是一些日常的维护操作： 1、放大LV容量 #lvextend -L +50G /dev/mapper/vgdisk-lvdisk #resize2fs /dev/mapper/vgdisk-lvdisk #df -h       显示成功加到117.58G   2、缩小LV容量 #umount /data #e2fsck -f /dev/mapper/vgdisk-lvdisk #resize2fs /dev/mapper/vgdisk-lvdisk 20G     #后面的20G表示缩小后的值。 #lvresize -L 20G /dev/mapper/vgdisk-lvdisk #mount /dev/mapper/vgdisk-lvdisk /data #df -h  #检查是否到达所要缩小到的大小   3、删除lv卷：lvremove /dev/mapper/vgdisk-lvdisk    删除vg组：vgremove /dev/vgdisk  删除物理卷：pvremove /dev/sda5   4、创建磁盘快照： #lvcreate -L 50G -s lvdiskbackup /dev/vgdisk/lvdisk     #创建快照 #mkdir /mnt/lvdiskbackup #mount /dev/vgdisk/lvdisk /mnt/lvdiskbackup #umount /mnt/lvdiskbackup #lvremove /dev/vgdisk/lvdiskbackup             #删除快照 最后检查数据完全一致，确认正常。