不重启增加centos根目录大小

添加新的磁盘

可以是在虚拟机上添加新磁盘，也可以在主机上插入新的磁盘。

一般来说，当我们在服务器上插入新的磁盘时，服务器是会对磁盘进行识别的。但是，有的时候服务器并没有对这些新插入的磁盘进行识别。这时，我们可以通过重启服务器，来使服务器重新加载硬盘。

在生产环境中我们的服务器上都存在着重要的服务，并不可以对服务器进行重启。下面介绍的就是无需重启服务器，使其识别新磁盘的方法。

发现新磁盘

fdisk -l

里面没有新加的磁盘。

查看主机总线号

ls /sys/class/scsi_host/

重新扫描SCSI总线添加设备

echo "- - -" > /sys/class/scsi_host/host0/scan
echo "- - -" > /sys/class/scsi_host/host1/scan
echo "- - -" > /sys/class/scsi_host/host2/scan

查看磁盘是否扫描出来

fdisk -l

对磁盘进行分区

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。
t  --设置分区类型
8e  类型为LVM
w  --写入分区表

再查看磁盘情况

[root@localhost Desktop]# fdisk -l /dev/sdb

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: 0xf0480a7c

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1            2048    41943039    20970496   8e  Linux LVM

注意
新分区的类型是Linux LVM

扩充根分区

查看卷分组

[root@localhost Desktop]# vgdisplay -v   ##找到centos
    Using volume group(s) on command line.
  --- Volume group ---
  VG Name               centos
  System ID             
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  4
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                3
  Open LV               3
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               99.51 GiB
  PE Size               4.00 MiB
  Total PE              25474
  Alloc PE / Size       25458 / 99.45 GiB
  Free  PE / Size       16 / 64.00 MiB
  VG UUID               eajt4v-Jdef-HZmX-U6AL-kOTp-lc1w-nHXcBe

为新增的分区创建物理卷

[root@localhost Desktop]# pvcreate /dev/sdb1
##提示是否擦除xfs签名，可以根据实际情况选择
WARNING: ext4 signature detected on /dev/sdb1 at offset 1080. Wipe it? [y/n]: y
  Wiping ext4 signature on /dev/sdb1.
  Physical volume "/dev/sdb1" successfully created

查看结果

[root@localhost Desktop]# pvdisplay /dev/sdb1##可以看到新创建的20GiB大小的物理卷：
  "/dev/sdb1" is a new physical volume of "20.00 GiB"
  --- NEW Physical volume ---
  PV Name               /dev/sdb1
  VG Name               
  PV Size               20.00 GiB
  Allocatable           NO
  PE Size               0   
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               JSpfvR-zsge-XRVU-CRT2-ubec-LcmO-oZtxmD

扩展卷分组

"centos"是vgdisplay命令查到的卷分组名

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

查看逻辑卷，并扩展逻辑卷

[root@registry mnt]# lvdisplay
  --- Logical volume ---
  LV Path                /dev/centos/swap
  LV Name                swap
  VG Name                centos
  LV UUID                pv0FXb-ADjF-qe8D-tXzo-T4sE-3MVH-YncDVN
  LV Write Access        read/write
  LV Creation host, time localhost.localdomain, 2018-11-08 16:41:14 +0800
  LV Status              available
  # open                 2
  LV Size                <7.88 GiB
  Current LE             2016
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:1
   
  --- Logical volume ---
  LV Path                /dev/centos/home
  LV Name                home
  VG Name                centos
  LV UUID                PEfA9A-3uOV-ocwc-Xr09-kk3p-2pqT-ssR24H
  LV Write Access        read/write
  LV Creation host, time localhost.localdomain, 2018-11-08 16:41:15 +0800
  LV Status              available
  # open                 1
  LV Size                23.48 GiB
  Current LE             6011
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:2
   
  --- Logical volume ---
  LV Path                /dev/centos/root
  LV Name                root
  VG Name                centos
  LV UUID                7NDe7m-rUYa-HqEn-qs2p-Zhth-Ww0h-VgtOAp
  LV Write Access        read/write
  LV Creation host, time localhost.localdomain, 2018-11-08 16:41:18 +0800
  LV Status              available
  # open                 1
  LV Size                <48.09 GiB
  Current LE             12311
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:0

可以看到/dev/centos/root目前的LV Size是48.09G。

[root@localhost Desktop]# lvextend -L +20G /dev/centos/root
Size of logical volume centos/root changed from 50.00 GiB (12800 extents) to 53.00 GiB (13568 extents).
Logical volume root successfully resized.

扩展后执行

[root@localhost Desktop]# xfs_growfs /dev/centos/root
meta-data=/dev/mapper/centos-root isize=256    agcount=4, agsize=3276800 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=0        finobt=0
data     =                       bsize=4096   blocks=13107200, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=0
log      =internal               bsize=4096   blocks=6400, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 13107200 to 13893632

 将文件系统扩大，完成。

查看结果

[root@localhost Desktop]# df -hT