Linux系统系统盘扩容，亲测可用

痛定思痛。 2022-12-28 01:54 233阅读 0赞

在开发中遇到磁盘空间不足的问题时，需要挂载一块新的磁盘，这时有2个操作。

1.  新建一个空目录，将硬盘并挂载到新的目录上，将数据转移至新的目录
2.  直接对根目录进行扩容

这里讲一下接下来直接对根目录进行扩容的操作步骤：

实验环境：RHEL7系统（默认已部署LVM）、VMware Workstation 12虚拟软件

1. 给虚拟机新增一块20GB的硬盘  
　　2. **使用命令 `lsblk` ，查看系统磁盘分区**，使用 fdisk /dev/sda （可能会是sdb，最后不要带数字）查看系统盘的分区类型，最后记得输入q不保存退出

[root@linuxprobe ~]# fdisk /dev/sda
    Welcome to fdisk (util-linux 2.23.2).
    
    Changes will remain in memory only, until you decide to write them.
    Be careful before using the write command.
    
    
    Command (m for help): p      //输入p查看分区信息
    
    Disk /dev/sda: 21.5 GB, 21474836480 bytes, 41943040 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: 0x00091636
    
       Device Boot      Start         End      Blocks   Id  System
    /dev/sda1   *        2048     1026047      512000   83  Linux
    /dev/sda2         1026048    41943039    20458496   8e  Linux LVM    //分区类型为Linux LVM
    　Command (m for help): q     //输入q不保存退出

第3步：对新硬盘进行分区，并设置分区类型

[root@linuxprobe ~]# fdisk /dev/sdb
    Welcome to fdisk (util-linux 2.23.2).
    
    Changes will remain in memory only, until you decide to write them.
    Be careful before using the write command.
    
    
    Command (m for help): n    //添加一个新分区
    Partition type:
       p   primary (0 primary, 0 extended, 4 free)
       e   extended
    Select (default p): p    //主分区
    Partition number (1-4, default 1): 1    //分区编号为1
    First sector (2048-41943039, default 2048): <此处按下回车键>
    Using default value 2048
    Last sector, +sectors or +size{K,M,G} (2048-41943039, default 41943039): +10G    //分区大小为10GB
    Partition 1 of type Linux and of size 10 GiB is set
    
    Command (m for help): p    //再次查看分区信息
    
    Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 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: 0x1894a517
    
       Device Boot      Start         End      Blocks   Id  System
    /dev/sdb1            2048    20973567    10485760   83  Linux     //新的分区添加成功，不过分区类型不对
    
    Command (m for help): t   //变更分区的类型
    Selected partition 1
    Hex code (type L to list all codes): 8e    //输入8e即"Linux LVM"
    Changed type of partition 'Linux' to 'Linux LVM'
    
    Command (m for help): p     //再次查看分区信息
    
    Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 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: 0x1894a517
    
       Device Boot      Start         End      Blocks   Id  System
    /dev/sdb1            2048    20973567    10485760   8e  Linux LVM   //分区类型变更成功，与系统分区一致
    
    Command (m for help): w      //最后记得要保存退出
    The partition table has been altered!
    
    Calling ioctl() to re-read partition table.
    Syncing disks.

上述操作需要重启才能生效，不过可以不要重启：输入命令`partprobe` ，强制让内核重新查找一次分区表

第4步：让新添加的硬盘分区支持LVM技术

[root@linuxprobe ~]# pvcreate /dev/sdb1
      Physical volume "/dev/sdb1" successfully created

第5步：查看当前系统的卷组，并将/dev/sdb1硬盘分区加入到卷组中

[root@linuxprobe ~]# vgdisplay 
      --- Volume group ---
      VG Name               rhel    //卷组名为"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               19.51 GiB     //卷组的总容量大小
      PE Size               4.00 MiB
      Total PE              4994
      Alloc PE / Size       4994 / 19.51 GiB
      Free  PE / Size       0 / 0   
      VG UUID               mGomiV-U0sF-wKii-YxOh-V7Gw-VEQ4-yIkcRD
    [root@linuxprobe ~]# vgextend rhel /dev/sdb1         //把/dev/sdb1硬盘分区加入到rhel卷组中
      Volume group "rhel" successfully extended
    [root@linuxprobe ~]# vgdisplay 
      --- Volume group ---
      VG Name               rhel
      System ID             
      Format                lvm2
      Metadata Areas        2
      Metadata Sequence No  4
      VG Access             read/write
      VG Status             resizable
      MAX LV                0
      Cur LV                2
      Open LV               2
      Max PV                0
      Cur PV                2
      Act PV                2
      VG Size               29.50 GiB      //卷组的容量增大了10GB
      PE Size               4.00 MiB
      Total PE              7553
      Alloc PE / Size       4994 / 19.51 GiB
      Free  PE / Size       2559 / 10.00 GiB      //记住空闲PE的数量，后面需要用到
      VG UUID               mGomiV-U0sF-wKii-YxOh-V7Gw-VEQ4-yIkcRD

第6步：查看当前逻辑卷信息

[root@linuxprobe ~]# lvdisplay 
      --- Logical volume ---
      LV Path                /dev/rhel/swap    //用来充当SWAP分区，我们这里不管它
      LV Name                swap
      VG Name                rhel
      LV UUID                d2gNWI-6Oin-9Q3r-OGLp-0nf5-0Dun-Z8EvgS
      LV Write Access        read/write
      LV Creation host, time localhost, 2020-02-15 20:19:35 +0800
      LV Status              available
      # open                 2
      LV Size                2.00 GiB
      Current LE             512
      Segments               1
      Allocation             inherit
      Read ahead sectors     auto
      - currently set to     256
      Block device           253:1
       
      --- Logical volume ---
      LV Path                /dev/rhel/root   //该逻辑卷实际就是Linux系统盘，我们将对它进行扩容
      LV Name                root     //逻辑卷名为root
      VG Name                rhel
      LV UUID                rI6Xvu-eCJx-0WFO-TuUj-LQWM-WuUc-3uE6zc
      LV Write Access        read/write
      LV Creation host, time localhost, 2020-02-15 20:19:35 +0800
      LV Status              available
      # open                 1
      LV Size                17.51 GiB   //逻辑卷的大小，即系统盘大小
      Current LE             4482
      Segments               1
      Allocation             inherit
      Read ahead sectors     auto
      - currently set to     256
      Block device           253:0

第7步：对root逻辑卷进行扩容操作

[root@linuxprobe ~]# lvextend -L +10G /dev/rhel/root    
      Extending logical volume root to 27.51 GiB
      Insufficient free space: 2560 extents needed, but only 2559 available   //显示实际空闲容量不足10GB，比10GB稍微小一点点
    [root@linuxprobe ~]# lvextend -l +2559 /dev/rhel/root    //这里改用 -l参数 进行扩容
      Extending logical volume root to 27.50 GiB
      Logical volume root successfully resized
    [root@linuxprobe ~]# lvdisplay 
    
    ----------------省略部分输出内容------------------------
       
      --- Logical volume ---
      LV Path                /dev/rhel/root
      LV Name                root
      VG Name                rhel
      LV UUID                rI6Xvu-eCJx-0WFO-TuUj-LQWM-WuUc-3uE6zc
      LV Write Access        read/write
      LV Creation host, time localhost, 2020-02-15 20:19:35 +0800
      LV Status              available
      # open                 1
      LV Size                27.50 GiB   //容量已从17.51GB提升至27.50GB
      Current LE             5762
      Segments               2
      Allocation             inherit
      Read ahead sectors     auto
      - currently set to     8192
      Block device           253:0

第8步：重置root逻辑卷的大小。xfs系统不需要先umount操作

[root@linuxprobe ~]# df -h
    Filesystem             Size  Used Avail Use% Mounted on
    /dev/mapper/rhel-root   18G  3.1G   15G  18% /           //重置之前，先查看当前系统盘的大小，此时显示为18GB
    devtmpfs               985M     0  985M   0% /dev
    tmpfs                  994M   80K  994M   1% /dev/shm
    tmpfs                  994M  8.9M  986M   1% /run
    tmpfs                  994M     0  994M   0% /sys/fs/cgroup
    /dev/sr0               3.5G  3.5G     0 100% /media/cdrom
    /dev/sda1              497M  119M  379M  24% /boot
    [root@linuxprobe ~]# xfs_growfs /dev/rhel/root        //重置root逻辑卷大小
    　　meta-data=/dev/mapper/rhel-root isize=256 agcount=4, agsize=1147392 blks
    　　= sectsz=512 attr=2, projid32bit=1
    　　= crc=0
    　　data = bsize=4096 blocks=4589568, imaxpct=25
    　　= sunit=0 swidth=0 blks
    　　naming =version 2 bsize=4096 ascii-ci=0 ftype=0
    　　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 4589568 to 7209984
    
    [root@linuxprobe ~]# df -h
    Filesystem             Size  Used Avail Use% Mounted on
    /dev/mapper/rhel-root   28G  17G   11G  62% /       //系统盘成功扩容至28G，增加了10GB容量，且重启依然生效
    devtmpfs               985M     0  985M   0% /dev
    tmpfs                  994M   80K  994M   1% /dev/shm
    tmpfs                  994M  8.9M  986M   1% /run
    tmpfs                  994M     0  994M   0% /sys/fs/cgroup
    /dev/sr0               3.5G  3.5G     0 100% /media/cdrom
    /dev/sda1              497M  119M  379M  24% /boot

至此，Linux系统盘扩容操作完毕。

知识补充：

1、重置逻辑卷命令 “xfs\_growfs /dev/rhel/root” 和 “xfs\_growfs /dev/mapper/rhel-root” 效果一样；

2、如果是ext4文件系统，重置命令为"resize2fs /dev/rhel/root"；

3、xfs文件系统只能扩容，不允许缩容。

[root@linuxprobe ~]# pvs
      PV         VG   Fmt  Attr PSize  PFree
      /dev/sda2  rhel lvm2 a--  19.51g    0 
      /dev/sdb1  rhel lvm2 a--  10.00g    0