计算机培训课件-LVM

一、什么是LVM？称为逻辑卷管理器，以卷为单位，放弃传统硬盘以分区为磁盘单位的这种方法，动态调整卷的大小，实现弹性的调整磁盘空间。LVM2支持功能：可以在线调整卷的大小可以建立卷的快照二、LVM的组成物理卷（PV）：一个物理的硬盘(/dev/hda1、/dev/hda2)也就是磁盘上分区卷组(VG)：将物理卷合并为一个抽象的概念物理块（PE）：当一个物理卷加入卷组时，它的空间被分为大小均匀的小的组块。物理块的大小在创建卷组时可以指定。默认4MB逻辑卷(LV)：理解是磁盘上的分区三、创建物理卷（1）准备硬盘，并分区（2）使用pvcreate命令创建物理卷语法：pvcreate设备名[root@localhost/]#pvcreate/dev/sdb1/dev/sdc1/dev/sdd1Physicalvolume/dev/sdb1successfullycreatedPhysicalvolume/dev/sdc1successfullycreatedPhysicalvolume/dev/sdd1successfullycreated四、创建卷组语法：vgcreateVGNAMEPVDEVICES...VGNAME:卷组的名称，我们可以自定义名称，但是注意该名称是唯一的，不要和/dev/其它设备名冲突。Pvdevices：是组成卷组的物理卷设备名[root@localhost/]#vgcreatevg0/dev/sd{b,c,d}1Volumegroupvg0successfullycreated五、创建逻辑卷语法：lvcreate[-LSIZE]-nLVNAMEVGNAMESIZE:逻辑卷的大小，如果没有指定SIZE，则将卷组所有可用空间作为该逻辑卷的大小。LVNAME：逻辑卷的名称VGNAME：卷组名称[root@localhost/]#lvcreate-L150MB-nlv0vg0Roundingupsizetofullphysicalextent152.00MBLogicalvolumelv0created为什么我们创建的是150M的逻辑卷，而创建了一个152MB的LV？答：卷组中物理卷将分成大小为4mb的PE，创建逻辑卷，卷组中的PE映射到逻辑卷中，也就是逻辑卷有大小为4MB的虚拟空间组成，一定是4mb的倍数。[root@localhost/]#[root@localhost/]#ls/dev/vg0/lv0当创建一个逻辑卷后，linux会自动产生逻辑卷的设备文件，一般是以/dev/VGNAME/LVNAME，可以使用/dev/VGNAME/中的内容判断有多少个LV六、卸载卷注意事项：卸载逻辑卷：最好先备份数据，由于文件系统是建立在逻辑卷上，当卸载逻辑卷后，文件系统也就不复存在。卸载卷组:先卸载该卷组上的所有逻辑卷，同理，卸载物理卷前，须先卸载卷组（1）卸载逻辑卷语法：lvremoveLVNAME[root@localhost/]#lvremove/dev/vg0/lv0Doyoureallywanttoremoveactivelogicalvolumelv0?[y/n]:yLogicalvolumelv0successfullyremoved（2）卸载卷组语法：vgremoveVGname[root@localhost/]#vgremovevg0Volumegroupvg0successfullyremoved（3）卸载物理卷语法：pvremovePVDEVICEroot@localhost/]#pvremove/dev/sd{b,c,d}1七、查看卷信息查看物理卷：pvdisplayPVDEVICE查看卷组：vgdisplayVGNAME查看逻辑卷：lvdisplayLVDEVICE（1）[root@localhost/]#pvdisplay/dev/sdb1---Physicalvolume---PVName/dev/sdb1VGNamevg0PVSize19.99GB/notusable1.43MBAllocatableyesPESize(KByte)4096TotalPE5118FreePE5080AllocatedPE38PVUUIDqrZ5h3-A79O-0QYg-1F3C-rqW4-Iti7-naVHS4（2）[root@localhost/]#vgdisplay---Volumegroup---VGNamevg0SystemIDFormatlvm2MetadataAreas2MetadataSequenceNo2VGAccessread/writeVGStatusresizableMAXLV0CurLV1OpenLV0MaxPV0CurPV2ActPV2VGSize39.98GBPESize4.00MBTotalPE10236AllocPE/Size38/152.00MBFreePE/Size10198/39.84GBVGUUIDlwaj3z-SQTh-DOxx-msIp-CN1i-x1SJ-utxZQI[root@localhost/]#lvdisplay---Logicalvolume---LVName/dev/vg0/lv0VGNamevg0LVUUIDtmutYa-nOS3-kBpr-NW4f-arej-rOqh-3vloY0LVWriteAccessread/writeLVStatusavailable#open0LVSize152.00MBCurrentLE38Segments1AllocationinheritReadaheadsectorsauto-currentlysetto256Blockdevice253:0八、调整卷组要放大卷组，有额外的物理卷vgextendVGNAMEPVDEVICE...VGNAME：卷组的名称PVDEVICE:物理卷的名称（1）添加物理卷添加硬盘并分区[root@localhost/]#pvcreate/dev/sdd1Physicalvolume/dev/sdd1successfullycreated（2）将物理卷加入到卷组中[root@localhost/]#vgdisplay|grepVGSizeVGSize39.98GB[root@localhost/]#vgextendvg0/dev/sdd1Volumegroupvg0successfullyextended[root@localhost/]#vgdisplay|grepVGSizeVGSize59.98GB要缩小[root@localhost/]#vgdisplay|grepVGSizeVGSize59.98GB[root@localhost/]#vgreducevg0/dev/sdd1Removed/dev/sdd1fromvolumegroupvg0[root@localhost/]#vgdisplay|grepVGSizeVGSize39.98GB九、调整逻辑卷按照如下步骤调整逻辑卷：放大先放大LV，然后在放大文件系统缩小先缩小文件系统，在缩小LV[root@localhost/]#mkfs-text3/dev/vg0/lv0[root@localhost/]#mkdir/lv0[root@localhost/]#mount/dev/vg0/lv0/lv0/[root@localhost/]#df-h文件系统容量已用可用已用%挂载点/dev/sda3115G2.1G107G2%//dev/sda199M12M83M12%/boottmpfs506M0506M0%/dev/shm/dev/mapper/vg0-lv0148M5.6M135M4%/lv0放大：[root@localhost/]#lvdisplay/dev/vg0/lv0|grepLVSizeLVSize152.00MB[root@localhost/]#lvextend-L+50M/dev/vg0/lv0Roundingupsizetofullphysicalextent52.00MBExtendinglogicalvolumelv0to204.00MBLogicalvolumelv0successfullyresized[root@localhost/]#lvdisplay/dev/vg0/lv0|grepLVSizeLVSize204.00MBroot@localhost/]#umount/lv0/[root@localhost/]#e2fsck–f/dev/vg0/lv0[root@localhost/]#resize2fs/dev/vg0/lv0resize2fs1.39(29-May-2006)Thefilesystemisalready208896blockslong.Nothingtodo![root@localhost/]#mount/dev/vg0/lv0/lv0/[root@localhost/]#df-h文件系统容量已用可用已用%挂载点/dev/sda3115G2.1G107G2%//dev/sda199M12M83M12%/boottmpfs506M0506M0%/dev/shm/dev/mapper/vg0-lv0198M5.8M182M4%/lv0缩小：先缩小文件系统，然后缩小LV[root@localhost/]#umount/lv0/[root@localhost/]#e2fsck-f/dev/vg0/lv0e2fsck1.39(29-May-2006)Pass1:Checkinginodes,blocks,andsizesPass2:CheckingdirectorystructurePass3:CheckingdirectoryconnectivityPass4:CheckingreferencecountsPass5:Checkinggroupsummaryinformation/dev/vg0/lv0:11/53248files(9.1%non-contiguous),12643/208896blocks[root@localhost/]#resize2fs/dev/vg0/lv0140Mresize2fs1.39(29-May-2006)Resizingthefilesystemon/dev/vg0/lv0to143360(1k)blocks.Thefilesystemon/dev/vg0/lv0isnow143360blockslong.[root@localhost/]#lvreduce-L-60M/dev/vg0/lv0WARNING:Reducingactivelogicalvolumeto144.00MBTHISMAYDESTROYYOURDATA(filesystemetc.)Doyoureallywanttoreducelv0?[y/n]:yReducinglogicalvolumelv0to144.00MBLogicalvolumelv0successfullyresized[root@localhost/]#lvdisplay/dev/vg0/lv0|grepLVSizeLVSize144.00MB[root@localhost/]#mount/dev/vg0/lv0/lv0/[root@localhost/]#df-h文件系统容量已用可用已用%挂载点/dev/sda3115G2.1G107G2%//dev/sda199M12M83M12%/boottmpfs506M0506M0%/dev/shm/dev/mapper/vg0-lv0136M5.6M125M5%/lv0[root@localhost/]#十、安装时创建逻辑卷十一、自动挂载/etc/fstab/dev/vg0/lv0/lv0ext3defaults00十二、LVM卷快照卷快照：保存创建快照当时状态，可以利用该功能备份文件系统中的数据内容。创建快照时候，保存所有的文