Centos 7 磁盘管理（LVM）

曾经终败给现在 2023-02-12 11:28 49阅读 0赞

## 一、无需重启主机增加磁盘 ##

1、为虚拟机添加多一块磁盘

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RsYWRhZ2lv_size_16_color_FFFFFF_t_70][]

2、检测磁盘空间

无法发现新增的2G磁盘

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RsYWRhZ2lv_size_16_color_FFFFFF_t_70 1][]

3、，重新扫描磁盘

通过重新扫描 SCSI （注：Small Computer System Interface 小型计算机系统接口）总线并添加 SCSI 设备，系统就可以扩展操作系统的物理卷磁盘空间，而且不需要重启虚拟机。

[root@localhost ~]# ls /sys/class/scsi_host/
    host0  host1  host2
    [root@localhost ~]# echo "- - -" > /sys/class/scsi_host/host0/scan
    [root@localhost ~]# echo "- - -" > /sys/class/scsi_host/host1/scan
    [root@localhost ~]# echo "- - -" > /sys/class/scsi_host/host2/scan

使用下面的命令来检查 SCSI 设备的名称，然后重新扫描 SCSI 总线。

[root@localhost ~]# ls /sys/class/scsi_device/
    0:0:0:0  0:0:1:0  2:0:0:0
    [root@localhost ~]# echo 1>/sys/class/scsi_device/0\:0\:0\:0/device/rescan
    [root@localhost ~]# echo 1>/sys/class/scsi_device/0\:0\:1\:0/device/rescan
    [root@localhost ~]# echo 1>/sys/class/scsi_device/2\:0\:0\:0/device/rescan

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RsYWRhZ2lv_size_16_color_FFFFFF_t_70 2][]

## 二、扩容主机现有的根分区 ##

如果磁盘使用率超过前期预算的，又需要保留所有数据，可以选择扩容根分区

1、查看磁盘使用率和“/”目录大小

[root@localhost ~]# df -HT
    Filesystem              Type      Size  Used Avail Use% Mounted on
    /dev/mapper/centos-root xfs       8.6G  1.1G  7.5G  13% /
    devtmpfs                devtmpfs  4.1G     0  4.1G   0% /dev
    tmpfs                   tmpfs     4.2G     0  4.2G   0% /dev/shm
    tmpfs                   tmpfs     4.2G  9.3M  4.1G   1% /run
    tmpfs                   tmpfs     4.2G     0  4.2G   0% /sys/fs/cgroup
    /dev/sda1               xfs       1.1G  153M  912M  15% /boot
    tmpfs                   tmpfs     821M     0  821M   0% /run/user/0

2、为新增的磁盘分区格式化

查看新的磁盘（是否存在/dev/sdb）

[root@localhost ~]# fdisk -l
    
    Disk /dev/sda: 10.7 GB, 10737418240 bytes, 20971520 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: 0x00002170
    
       Device Boot      Start         End      Blocks   Id  System
    /dev/sda1   *        2048     2099199     1048576   83  Linux
    /dev/sda2         2099200    20971519     9436160   8e  Linux LVM
    
    Disk /dev/mapper/centos-root: 8585 MB, 8585740288 bytes, 16769024 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/centos-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
    
    
    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

对磁盘进行分区

[root@localhost ~]# fdisk /dev/sdb
    
    fdisk的交互模式，依次输入
    n  --创建新分区
    p  --创建主分区
    <回车>  --默认分区编号
    <回车>  --默认起始扇区位置。
    <回车>  --默认结束扇区位置。
    w  --写入分区表

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RsYWRhZ2lv_size_16_color_FFFFFF_t_70 3][]

3、再查看磁盘能看到新增的/dev/sdb1

[root@localhost ~]# 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 label type: dos
    Disk identifier: 0x07276705
    
       Device Boot      Start         End      Blocks   Id  System
    /dev/sdb1            2048     4194303     2096128   83  Linux

4、将新磁盘分区扩容到根分区 "/"

4.1、查看卷分组

[root@localhost ~]# vgdisplay -v
      --- Volume group ---
      VG Name               centos
      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               <9.00 GiB
      PE Size               4.00 MiB
      Total PE              2303
      Alloc PE / Size       2303 / <9.00 GiB
      Free  PE / Size       0 / 0   
      VG UUID               DmqyXY-Kj13-sfSR-v9i5-wpLc-ht7c-kPJIvC
    ......
    
      --- Physical volumes ---
      PV Name               /dev/sda2     
      PV UUID               7CPA1z-xrMe-CAo7-g14k-cL8B-zgm2-vXbuP3
      PV Status             allocatable
      Total PE / Free PE    2303 / 0

4.2、为新增的分区创建物理卷

[root@localhost ~]# pvcreate /dev/sdb1
      Physical volume "/dev/sdb1" successfully created.
    
    
    
    查看创建结果，有新建的/dev/sdb1，大小为2G
    [root@localhost ~]# pvdisplay 
      --- Physical volume ---
      PV Name               /dev/sda2
      VG Name               centos
      PV Size               <9.00 GiB / not usable 3.00 MiB
      Allocatable           yes (but full)
      PE Size               4.00 MiB
      Total PE              2303
      Free PE               0
      Allocated PE          2303
      PV UUID               7CPA1z-xrMe-CAo7-g14k-cL8B-zgm2-vXbuP3
       
      "/dev/sdb1" is a new physical volume of "<2.00 GiB"
      --- NEW Physical volume ---
      PV Name               /dev/sdb1
      VG Name               
      PV Size               <2.00 GiB
      Allocatable           NO
      PE Size               0   
      Total PE              0
      Free PE               0
      Allocated PE          0
      PV UUID               SnXl2W-LsFp-FHUT-M4Ze-yZy9-Y6WH-p3kQ0S

4.3、扩展卷分组，“centos”就是前面使用vgdisplay查看到的主机原本的卷分组名

[root@localhost ~]# vgextend centos /dev/sdb1
      Volume group "centos" successfully extended

4.4、查看逻辑卷，并扩展逻辑卷

目前/dev/centos/root的LV Size大小为8G

[root@localhost ~]# lvdisplay 
      --- Logical volume ---
      LV Path                /dev/centos/swap
      LV Name                swap
      VG Name                centos
      LV UUID                4U7aBO-Nknq-ZkLc-sLXU-bGpH-Ru9B-5lzejQ
      LV Write Access        read/write
      LV Creation host, time localhost, 2020-05-08 02:15:24 -0400
      LV Status              available
      # open                 2
      LV Size                1.00 GiB
      Current LE             256
      Segments               1
      Allocation             inherit
      Read ahead sectors     auto
      - currently set to     8192
      Block device           253:1
       
      --- Logical volume ---
      LV Path                /dev/centos/root
      LV Name                root
      VG Name                centos
      LV UUID                D20gW5-4CiO-Pdfp-68yn-t4wG-h1cs-aw4ge7
      LV Write Access        read/write
      LV Creation host, time localhost, 2020-05-08 02:15:26 -0400
      LV Status              available
      # open                 1
      LV Size                <8.00 GiB
      Current LE             2047
      Segments               1
      Allocation             inherit
      Read ahead sectors     auto
      - currently set to     8192
      Block device           253:0

扩展操作

[root@localhost ~]# lvextend -L +1G /dev/centos/root 
      Size of logical volume centos/root changed from <8.00 GiB (2047 extents) to <9.00 GiB (2303 extents).
      Logical volume centos/root successfully resized.

注意：不能全部把2G空间都扩展，因为实际没有这么大的空间

报错如下，提只有511可用
    [root@localhost ~]# lvextend -L +2G /dev/centos/root 
      Insufficient free space: 512 extents needed, but only 511 available
    
    执行pvdisplay可以看到可用的PE数量是511,而且每个PE大小是4.00MiB，所以实际空间并没有2G
    [root@localhost ~]# pvdisplay 
      --- Physical volume ---
      PV Name               /dev/sda2
      VG Name               centos
      PV Size               <9.00 GiB / not usable 3.00 MiB
      Allocatable           yes (but full)
      PE Size               4.00 MiB
      Total PE              2303
      Free PE               0
      Allocated PE          2303
      PV UUID               7CPA1z-xrMe-CAo7-g14k-cL8B-zgm2-vXbuP3
       
      --- Physical volume ---
      PV Name               /dev/sdb1
      VG Name               centos
      PV Size               <2.00 GiB / not usable 3.00 MiB
      Allocatable           yes 
      PE Size               4.00 MiB
      Total PE              511
      Free PE               511
      Allocated PE          0
      PV UUID               SnXl2W-LsFp-FHUT-M4Ze-yZy9-Y6WH-p3kQ0S

4.5、因为安装CentOS用的xfs分区，所以使用命令*xfs\_growfs*扩展文件系统大小。

[root@localhost ~]# xfs_growfs /dev/centos/root 
    meta-data=/dev/mapper/centos-root isize=512    agcount=4, agsize=524032 blks
             =                       sectsz=512   attr=2, projid32bit=1
             =                       crc=1        finobt=0 spinodes=0
    data     =                       bsize=4096   blocks=2096128, imaxpct=25
             =                       sunit=0      swidth=0 blks
    naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
    log      =internal               bsize=4096   blocks=2560, version=2
             =                       sectsz=512   sunit=0 blks, lazy-count=1
    realtime =none                   extsz=4096   blocks=0, rtextents=0
    data blocks changed from 2096128 to 2358272

5、再次查看根目录大小，/dev/mapper/centos-root已经扩容到9G

[root@localhost ~]# df -HT
    Filesystem              Type      Size  Used Avail Use% Mounted on
    /dev/mapper/centos-root xfs       9.7G  1.1G  8.6G  12% /
    devtmpfs                devtmpfs  4.1G     0  4.1G   0% /dev
    tmpfs                   tmpfs     4.2G     0  4.2G   0% /dev/shm
    tmpfs                   tmpfs     4.2G  9.3M  4.1G   1% /run
    tmpfs                   tmpfs     4.2G     0  4.2G   0% /sys/fs/cgroup
    /dev/sda1               xfs       1.1G  153M  912M  15% /boot
    tmpfs                   tmpfs     821M     0  821M   0% /run/user/0

## 三、为主机挂载新的磁盘空间 ##

不改变原主机磁盘状态，新挂载一个磁盘做数据存储

1、一样先看是否能看到新添加的磁盘，不能就执行第一大点的操作

2、对新磁盘进行分区

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RsYWRhZ2lv_size_16_color_FFFFFF_t_70 4][]

再查看磁盘个数与分区情况

[root@localhost ~]# 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 label type: dos
    Disk identifier: 0xaaed78bd
    
       Device Boot      Start         End      Blocks   Id  System
    /dev/sdb1            2048     4194303     2096128   83  Linux

3、格式化

[root@localhost ~]# partprobe /dev/sdb
    [root@localhost ~]# mkfs.ext3 /dev/sdb1

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RsYWRhZ2lv_size_16_color_FFFFFF_t_70 5][]

4、创建挂载目录

[root@localhost ~]# mkdir /mydata

5、挂载分区

[root@localhost ~]# mount /dev/sdb1  /mydata

6、创建开机自动挂载

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RsYWRhZ2lv_size_16_color_FFFFFF_t_70 6][]

7、查看挂载

![20200526134542959.png][]

8、也可以通过磁盘的UUID进行挂载

查看uuid

[root@localhost ~]# blkid

![20200526134453286.png][]

8、挂载

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RsYWRhZ2lv_size_16_color_FFFFFF_t_70 7][]

9、重启，再查看挂载

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RsYWRhZ2lv_size_16_color_FFFFFF_t_70 8][]

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[20200526134542959.png]: https://img-blog.csdnimg.cn/20200526134542959.png
[20200526134453286.png]: https://img-blog.csdnimg.cn/20200526134453286.png
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