1）逻辑卷的管理 准备两个10GB的分区，建立卷组vgnsd 再准备一个10GB的分区，建立卷组vgdata 从卷组vgnsd中划出一个15GB的逻辑卷lvhome 从卷组vgdata中划出一个4GB的逻辑卷lvswap
2）逻辑卷的实际使用 将/home目录迁移到逻辑卷lvhome上 将逻辑卷lvswap扩展到交换空间 确保上述卷开机后自动挂载
方案 LVM是在Linux中特殊的磁盘卷，它可以整合多个小的磁盘或分区，并且空间能够实现伸缩。创建及使用LVM过程：创建PV --> 创建VG --> 创建LVM --> 格式化LVM --> mount。 用来管理LVM命令主要命令的语法： pvcreate 设备名… vgcreate 卷组名 物理卷… lvcreate -L 大小 -n 逻辑卷名 卷组名
步骤 实现此案例需要按照如下步骤进行。
步骤一：逻辑卷的管理 准备两个10GB的分区，建立卷组vgnsd，命令操作如下所示：
[root@localhost /]# parted /dev/sdb print //输出sdb分区表 Model: VMware, VMware Virtual S (scsi) Disk /dev/sdb: 85.9GB Sector size (logical/physical): 512B/512B Partition Table: msdos Number Start End Size Type File system 标志 1 512B 1000MB 1000MB primary ext4 2 1000MB 2000MB 999MB primary ext4 3 2000MB 85.9GB 83.9GB extended lba 5 2001MB 3000MB 999MB logical [root@localhost /]# parted /dev/sdb mktable gpt //将sdb分区方式更改为gpt 警告: 正在使用 /dev/sdb 上的分区。 忽略/Ignore/放弃/Cancel? i 警告: The existing disk label on /dev/sdb will be destroyed and all data on this disk will be lost. Do you want to continue? 是/Yes/否/No? y 警告: WARNING: the kernel failed to re-read the partition table on /dev/sdb (设备或资源忙). As a result, it may not reflect all of your changes until after reboot. [root@localhost /]# parted /dev/sdb print Model: VMware, VMware Virtual S (scsi) Disk /dev/sdb: 85.9GB Sector size (logical/physical): 512B/512B Partition Table: gpt Number Start End Size File system Name 标志 [root@localhost /]# parted /dev/sdb mkpart primary 0 10G //划分10G分区 警告: The resulting partition is not properly aligned for best performance. 忽略/Ignore/放弃/Cancel? i 警告: WARNING: the kernel failed to re-read the partition table on /dev/sdb (设备或资源忙). As a result, it may not reflect all of your changes until after reboot. [root@localhost /]# parted /dev/sdb print Model: VMware, VMware Virtual S (scsi) Disk /dev/sdb: 85.9GB Sector size (logical/physical): 512B/512B Partition Table: gpt Number Start End Size File system Name 标志 1 17.4kB 10.0GB 10000MB primary [root@localhost /]# parted /dev/sdb mkpart primary 10G 20G 警告: WARNING: the kernel failed to re-read the partition table on /dev/sdb (设备或资源忙). As a result, it may not reflect all of your changes until after reboot. [root@localhost /]# parted /dev/sdb mkpart primary 20G 30G 警告: WARNING: the kernel failed to re-read the partition table on /dev/sdb (设备或资源忙). As a result, it may not reflect all of your changes until after reboot. [root@localhost /]# parted /dev/sdb print Model: VMware, VMware Virtual S (scsi) Disk /dev/sdb: 85.9GB Sector size (logical/physical): 512B/512B Partition Table: gpt Number Start End Size File system Name 标志 1 17.4kB 10.0GB 10000MB primary 2 10.0GB 20.0GB 9999MB primary 3 20.0GB 30.0GB 10.0GB primary [root@localhost /]#这个时候需要系统重新识别GPT分区模式以及新的分区表，建议大家重启。 [root@localhost ~]# init 6 可以给LVM分区加一个标志以方便管理及查看。
[root@localhost ~]# parted /dev/sdb print Model: VMware, VMware Virtual S (scsi) Disk /dev/sdb: 85.9GB Sector size (logical/physical): 512B/512B Partition Table: gpt Number Start End Size File system Name 标志 1 17.4kB 10.0GB 10000MB primary 2 10.0GB 20.0GB 9999MB primary 3 20.0GB 30.0GB 10.0GB primary [root@localhost ~]# parted /dev/sdb set 1 lvm on //set：添加标志；1：为分区编号；lvm：标志；on：开启 信息: You may need to update /etc/fstab. [root@localhost ~]# parted /dev/sdb print Model: VMware, VMware Virtual S (scsi) Disk /dev/sdb: 85.9GB Sector size (logical/physical): 512B/512B Partition Table: gpt Number Start End Size File system Name 标志 1 17.4kB 10.0GB 10000MB primary lvm 2 10.0GB 20.0GB 9999MB primary 3 20.0GB 30.0GB 10.0GB primary [root@localhost ~]# parted /dev/sdb set 2 lvm on 信息: You may need to update /etc/fstab. [root@localhost ~]# parted /dev/sdb set 3 lvm on 信息: You may need to update /etc/fstab. [root@localhost ~]# parted /dev/sdb print Model: VMware, VMware Virtual S (scsi) Disk /dev/sdb: 85.9GB Sector size (logical/physical): 512B/512B Partition Table: gpt Number Start End Size File system Name 标志 1 17.4kB 10.0GB 10000MB primary lvm 2 10.0GB 20.0GB 9999MB primary lvm 3 20.0GB 30.0GB 10.0GB primary lvm [root@localhost ~]#准备两个10GB的分区，创建卷组vgnsd，首先要创建物理卷：
[root@localhost ~]# pvscan //查看现有物理卷 No matching physical volumes found [root@localhost ~]# ls /dev/sdb[1-3] //查看是否识别新的分区 /dev/sdb1 /dev/sdb2 /dev/sdb3 [root@localhost ~]# pvcreate /dev/sdb1 /dev/sdb2 /dev/sdb3 //创建物理分区 Physical volume "/dev/sdb1" successfully created Physical volume "/dev/sdb2" successfully created Physical volume "/dev/sdb3" successfully created [root@localhost ~]# pvscan //查看结果 PV /dev/sdb1 lvm2 [9.31 GiB] PV /dev/sdb2 lvm2 [9.31 GiB] PV /dev/sdb3 lvm2 [9.31 GiB] Total: 3 [27.94 GiB] / in use: 0 [0 ] / in no VG: 3 [27.94 GiB] [root@localhost ~]# vgscan //查看现有卷组 Reading all physical volumes. This may take a while... No volume groups found [root@localhost ~]# vgcreate vgnsd /dev/sdb1 /dev/sdb2 //创建卷组 Volume group "vgnsd" successfully created [root@localhost ~]# vgscan //查看结果 Reading all physical volumes. This may take a while... Found volume group "vgnsd" using metadata type lvm2再准备一个10GB的分区，建立卷组vgdata：
[root@localhost ~]# pvscan //查看所有物理卷 PV /dev/sdb1 VG vgnsd lvm2 [9.31 GiB / 9.31 GiB free] PV /dev/sdb2 VG vgnsd lvm2 [9.31 GiB / 9.31 GiB free] PV /dev/sdb3 lvm2 [9.31 GiB] Total: 3 [27.93 GiB] / in use: 2 [18.62 GiB] / in no VG: 1 [9.31 GiB] [root@localhost ~]# vgcreate vgdata /dev/sdb3 //创建卷组vgdata Volume group "vgdata" successfully created [root@localhost ~]# pvscan //查看所有物理卷 PV /dev/sdb3 VG vgdata lvm2 [9.31 GiB / 9.31 GiB free] PV /dev/sdb1 VG vgnsd lvm2 [9.31 GiB / 9.31 GiB free] PV /dev/sdb2 VG vgnsd lvm2 [9.31 GiB / 9.31 GiB free] Total: 3 [27.93 GiB] / in use: 3 [27.93 GiB] / in no VG: 0 [0 ] [root@localhost ~]# vgscan //查看所有卷组 Reading all physical volumes. This may take a while... Found volume group "vgdata" using metadata type lvm2 Found volume group "vgnsd" using metadata type lvm2 [root@localhost ~]#从卷组vgnsd中划出一个15GB的逻辑卷lvhome：
[root@localhost ~]# lvs //查看所有逻辑卷 [root@localhost ~]# [root@localhost ~]# lvcreate -L 15G -n lvhome vgnsd //划分逻辑卷 Logical volume "lvhome" created [root@localhost ~]# lvs //查看结果 LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert lvhome vgnsd -wi-a----- 15.00g [root@localhost ~]#从卷组vgdata中划出一个4GB的逻辑卷lvswap：
[root@localhost ~]# lvs //查看所有逻辑卷 LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert lvhome vgnsd -wi-a----- 15.00g [root@localhost ~]# lvcreate -L 4G -n lvswap vgdata //划分逻辑卷 Logical volume "lvswap" created [root@localhost ~]# lvs //查看结果 LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert lvswap vgdata -wi-a----- 4.00g lvhome vgnsd -wi-a----- 15.00g [root@localhost ~]#步骤二：逻辑卷的实际使用 将/home目录迁移到逻辑卷lvhome上。 分析： 原来/home目录所占用空间来源于根分区，现在想把/home目录迁移到其他分区上，以减小根分区压力。具体思路是：先将home目录里内容作一个备份，然后在将lvhome逻辑卷挂载到/home目录，再将内容还原。需注意在挂载使用前需将lvhome格式化。 命令操作如下所示：
[root@localhost ~]# mkdir /home.bak //创建备份目录 [root@localhost ~]# ls /home gelin01 gelin02 ht02 john kaka lily lisi mike zhangsan [root@localhost ~]# mv /home/* /home.bak //备份home目录下内容 [root@localhost ~]# mkfs.ext4 /dev/vgnsd/lvhome //格式化逻辑卷 [root@localhost ~]# mount /dev/vgnsd/lvhome /home //挂载lvhome逻辑卷 [root@localhost ~]# mount | grep home //查看挂载结果 /dev/mapper/vgnsd-lvhome on /home type ext4 (rw) [root@localhost ~]# mv /home.bak/* /home //还原home内容 [root@localhost ~]# ls /home gelin01 gelin02 ht02 john kaka lily lisi lost+found mike zhangsan [root@localhost ~]#将逻辑卷lvswap扩展到交换空间。 分析： 将lvswap逻辑卷格式化swap文件系统，在启用即可。
[root@localhost ~]# mkswap /dev/vgdata/lvswap //格式化成swap文件系统 mkswap: /dev/vgdata/lvswap: warning: don't erase bootbits sectors on whole disk. Use -f to force. Setting up swapspace version 1, size = 4194300 KiB no label, UUID=ba5895f4-0662-40e0-97ee-41cb095fddd2 [root@localhost ~]# swapon /dev/vgdata/lvswap //启用 [root@localhost ~]# swapon –s //查看 Filename Type Size Used Priority /dev/sda5 partition 8388600 0 -1 /dev/sda8 partition 1951736 0 -2 /dev/dm-1 partition 4194296 0 -3 [root@localhost ~]# ls -l /dev/vgdata/lvswap //可以看出lvswap是一个链接文件 lrwxrwxrwx. 1 root root 7 2月 28 15:15 /dev/vgdata/lvswap -> ../dm-1 [root@localhost ~]#确保上述卷开机后自动挂载。 分析： 将设备和参数写入到/etc/fstab配置文件即可。
[root@localhost ~]# vim /etc/fstab [root@localhost ~]# tail -n 2 /etc/fstab /dev/vgnsd/lvhome /home ext4 defaults 0 0 /dev/vgdata/lvswap swap swap defaults 0 0 [root@localhost ~]# mount –a //是否有错误输出 [root@localhost ~]# mount | grep lvhome //查看挂载情况 /dev/mapper/vgnsd-lvhome on /home type ext4 (rw) [root@localhost ~]#