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  • LVM逻辑卷管理测试——创建逻辑卷

    虚拟机里再添加两块硬盘,如下所示:

    启动系统后,我们可以看到新添加的两块硬盘为/dev/sdb和/dev/sdc.每个2GB。

    [root@lxjtest ~]# fdisk -l
    
    Disk /dev/sdb: 2147 MB, 2147483648 bytes, 4194304 sectors
    Units = sectors of 1 * 512 = 512 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes
    
    
    Disk /dev/sdc: 2147 MB, 2147483648 bytes, 4194304 sectors
    Units = sectors of 1 * 512 = 512 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes
    
    
    Disk /dev/sda: 5368 MB, 5368709120 bytes, 10485760 sectors
    Units = sectors of 1 * 512 = 512 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes
    Disk label type: dos
    Disk identifier: 0x0006ae1e
    
       Device Boot      Start         End      Blocks   Id  System
    /dev/sda1   *        2048      616447      307200   83  Linux
    /dev/sda2          616448    10485759     4934656   8e  Linux LVM ----这个分区是安装系统过程中创建的逻辑卷
    
    Disk /dev/mapper/rhel-root: 3976 MB, 3976200192 bytes, 7766016 sectors
    Units = sectors of 1 * 512 = 512 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes
    
    
    Disk /dev/mapper/rhel-swap: 1073 MB, 1073741824 bytes, 2097152 sectors
    Units = sectors of 1 * 512 = 512 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes

    下面我们将对这两块新的硬盘先进行创建物理卷操作,可以简单理解成让硬盘设备支持了LVM技术,然后对两块硬盘进行卷组合并,卷组的名称可以由您来自定义,接下来是把合并后的卷组根据需求再切割出一个约为200M的逻辑卷设备,最后把这个逻辑卷设备格式化成ext4文件系统后挂载使用。

    第一步:让新添加的两块硬盘设备支持LVM逻辑卷管理器技术,并查看创建的物理卷信息

    [root@lxjtest ~]# pvcreate /dev/sdb /dev/sdc
      Physical volume "/dev/sdb" successfully created
      Physical volume "/dev/sdc" successfully created
    [root@lxjtest ~]# pvdisplay
      --- Physical volume ---
      PV Name               /dev/sda2
      VG Name               rhel
      PV Size               4.71 GiB / not usable 3.00 MiB
      Allocatable           yes (but full)
      PE Size               4.00 MiB
      Total PE              1204
      Free PE               0
      Allocated PE          1204
      PV UUID               V3kA1X-l7dr-03p4-HZcu-Ebj3-FRvb-r5vGMd
       
      --- Physical volume --- 以下两个是刚创建的物理卷设备
      PV Name               /dev/sdb
      VG Name               testVG
      PV Size               2.00 GiB / not usable 4.00 MiB
      Allocatable           yes 
      PE Size               4.00 MiB  --默认情况下,PE大小都为4MB。
      Total PE              511       ---PE基本单元的个数
      Free PE               511
      Allocated PE          0
      PV UUID               InfACr-fq1t-yi95-K1K3-dOHU-uezl-gfiPVa
       
      --- Physical volume ---
      PV Name               /dev/sdc
      VG Name               testVG
      PV Size               2.00 GiB / not usable 4.00 MiB
      Allocatable           yes 
      PE Size               4.00 MiB
      Total PE              511
      Free PE               511
      Allocated PE          0
      PV UUID               aOtJga-uWop-ldnv-xIcj-TcLE-aq18-SrJO3p

    第二步:把两块硬盘加入到testVG卷组中,然后查看卷组信息

    [root@lxjtest ~]# vgcreate testVG /dev/sdb /dev/sdc
      Volume group "testVG" successfully created
    [root@lxjtest ~]# vgdisplay
      --- Volume group --- 这个rhel的卷组是在安装系统的过程中自动创建的
      VG Name               rhel
      System ID             
      Format                lvm2
      Metadata Areas        1
      Metadata Sequence No  3
      VG Access             read/write
      VG Status             resizable
      MAX LV                0
      Cur LV                2
      Open LV               2
      Max PV                0
      Cur PV                1
      Act PV                1
      VG Size               4.70 GiB
      PE Size               4.00 MiB
      Total PE              1204
      Alloc PE / Size       1204 / 4.70 GiB
      Free  PE / Size       0 / 0   
      VG UUID               LrU5p2-fp7C-B7cZ-LFxL-g35x-uxrY-W8w93C
       
      --- Volume group ---  刚创建的卷组testVG
      VG Name               testVG
      System ID             
      Format                lvm2
      Metadata Areas        2
      Metadata Sequence No  1
      VG Access             read/write
      VG Status             resizable
      MAX LV                0
      Cur LV                0
      Open LV               0
      Max PV                0
      Cur PV                2
      Act PV                2
      VG Size               3.99 GiB
      PE Size               4.00 MiB
      Total PE              1022  --总的PE等于上一步中的物理卷/dev/sdb 和/dev/sdc的Total PE之和
      Alloc PE / Size       0 / 0   
      Free  PE / Size       1022 / 3.99 GiB
      VG UUID               b3mykq-kcsp-Hdh4-rAos-vutt-ontI-6AWJ5K

    第三步:从卷组testVG中分出一个200MB的逻辑卷设备

    在LVM逻辑卷管理器对LV逻辑卷的切割上面有两种计量单位,第一种是常见以-L参数来以容量单位为对象,例如使用-L 200M来生成一个大小为200M的逻辑卷,还可以使用-l参数来指定要使用PE基本单元的个数,默认每个PE的大小为4M,因此允许使用-l 50来生成一个大小为50*4M=200M的逻辑卷:

    [root@lxjtest ~]# lvcreate -n fuck_lv1 -L 200M testVG
      Logical volume "fuck_lv1" created.
    [root@lxjtest ~]# lvs
      LV       VG     Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
      root     rhel   -wi-ao----   3.70g                                                    
      swap     rhel   -wi-ao----   1.00g                                                    
      fuck_lv1 testVG -wi-a----- 200.00m                                                    
    [root@lxjtest ~]# lvs testVG
      LV       VG     Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
      fuck_lv1 testVG -wi-a----- 200.00m                                            
    [root@lxjtest ~]# lvdisplay testVG
      --- Logical volume ---  从下面的信息可以看出,卷组testVG目前只分了一个逻辑卷fuck_lv1
      LV Path                /dev/testVG/fuck_lv1   --系统会把逻辑卷设备放到/dev/目录下
      LV Name                fuck_lv1
      VG Name                testVG
      LV UUID                RKzHdO-NX2i-Za40-kWNg-RIox-yi9j-z9251R
      LV Write Access        read/write
      LV Creation host, time lxjtest.rusky.com, 2017-08-07 23:35:10 -0400
      LV Status              available
      # open                 0
      LV Size                200.00 MiB
      Current LE             50
      Segments               1
      Allocation             inherit
      Read ahead sectors     auto
      - currently set to     8192
      Block device           253:2
       

    第四步:把创建好的逻辑卷fuck_lv1格式化后挂载使用:

    Linux系统会把LVM逻辑卷管理器中的逻辑卷设备存放在/dev设备目录中(实际上是做了一个符号链接,但读者们无需关心),同时会以卷组的名称来建立一个目录,其中保存有逻辑卷的设备映射文件(即/dev/卷组名称/逻辑卷名称)。

    [root@lxjtest ~]# mkfs.ext4 /dev/testVG/fuck_lv1
    mke2fs 1.42.9 (28-Dec-2013)
    Filesystem label=
    OS type: Linux
    Block size=1024 (log=0)
    Fragment size=1024 (log=0)
    Stride=0 blocks, Stripe width=0 blocks
    51200 inodes, 204800 blocks
    10240 blocks (5.00%) reserved for the super user
    First data block=1
    Maximum filesystem blocks=33816576
    25 block groups
    8192 blocks per group, 8192 fragments per group
    2048 inodes per group
    Superblock backups stored on blocks: 
            8193, 24577, 40961, 57345, 73729
    
    Allocating group tables: done                            
    Writing inode tables: done                            
    Creating journal (4096 blocks): done
    Writing superblocks and filesystem accounting information: done 
    
    [root@lxjtest ~]# 
    [root@lxjtest ~]# mkdir /testLVM
    [root@lxjtest ~]# mount /dev/testVG/fuck_lv1  /testLVM/
    [root@lxjtest ~]# df -h

    第5步:查看挂载状态,并写入到配置文件永久生效:

    [root@lxjtest ~]# df -h
    Filesystem                   Size  Used Avail Use% Mounted on
    /dev/mapper/rhel-root        3.7G  896M  2.9G  24% /
    devtmpfs                     910M     0  910M   0% /dev
    tmpfs                        920M     0  920M   0% /dev/shm
    tmpfs                        920M  8.4M  912M   1% /run
    tmpfs                        920M     0  920M   0% /sys/fs/cgroup
    /dev/sda1                    297M  114M  184M  39% /boot
    tmpfs                        184M     0  184M   0% /run/user/0
    /dev/mapper/testVG-fuck_lv1  190M  1.6M  175M   1% /testLVM

    修改/etc/fstab文件,增加如下一行:

    /dev/testVG/fuck_lv1    /testLVM                ext4    defaults        0 0      

     这样,系统重启后,我们创建的逻辑卷/dev/testVG/fuck_lv1就会自动挂载到/testLVM目录下。

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  • 原文地址:https://www.cnblogs.com/rusking/p/7306146.html
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