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Linux运维新手要掌握的扩展Linux系统根分区方法

发布：Linux培训
来源：职场技巧分享
时间：2020-08-20 15:19

今天小编要跟大家分享的文章是关于Linux运维新手要掌握的扩展Linux系统根分区方法。为了完成此实验，请确保Linux系统有足够的磁盘空间，如果磁盘空间不足则需要添加磁盘。本文档扩展Linux系统根分区的方法是在虚拟环境下做的，在生产环境下同样适用。

环境：VMware虚拟机Red Hat 6.5

技术：逻辑卷管理(LVM)

Linux 系统根分区方法

具体步骤：

1、查看磁盘空间

[root@localhost ~]# df -h
#查看磁盘空间，根分区的大小是18G，已经用了43%。
Filesystem                    Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root   18G  7.0G  9.5G  43% /
tmpfs                         2.0G   76K  2.0G   1% /dev/shm
/dev/sda1                     485M   40M  421M   9% /boot
/dev/sr0                      3.6G  3.6G     0 100% /media/cdrom

2、创建磁盘分区

[root@localhost ~]# fdisk -l

Disk /dev/sda: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00083529

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          64      512000   83  Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2              64        2611    20458496   8e  Linux LVM
#/dev/sdb盘还有足够的空间
Disk /dev/sdb: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/mapper/VolGroup-lv_root: 18.8 GB, 18798870528 bytes
255 heads, 63 sectors/track, 2285 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/mapper/VolGroup-lv_swap: 2147 MB, 2147483648 bytes
255 heads, 63 sectors/track, 261 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
[root@localhost ~]# fdisk /dev/sdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0xac7c929b.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
         switch off the mode (command 'c') and change display units to
         sectors (command 'u').

Command (m for help): p
Disk /dev/sdb: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xac7c929b
Device Boot      Start         End      Blocks   Id  System
Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 1#分区号
First cylinder (1-2610, default 1):  #回车用默认的
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-2610, default 2610): #回车用默认的
Using default value 2610

Command (m for help): t #改变类型
Selected partition 1
Hex code (type L to list codes): 8e #LVM的分区代码
Changed system type of partition 1 to 8e (Linux LVM)
Command (m for help): p
Disk /dev/sdb: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xac7c929b

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1        2610    20964793+  8e  Linux LVM

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.
[root@localhost ~]# partprobe
#将磁盘分区表变化信息通知内核，请求操作系统重新加载分区表，有些小报错不要紧。
Warning: WARNING: the kernel failed to re-read the partition table on /dev/sda (Device or resource busy).  As a result, it may not reflect all of your changes until after reboot.
Warning: WARNING: the kernel failed to re-read the partition table on /dev/sdb (Device or resource busy).  As a result, it may not reflect all of your changes until after reboot.
Warning: Unable to open /dev/sr0 read-write (Read-only file system).  /dev/sr0 has been opened read-only.
Warning: Unable to open /dev/sr0 read-write (Read-only file system).  /dev/sr0 has been opened read-only.
Error: Invalid partition table - recursive partition on /dev/sr0.

3、创建物理卷

4、扩展卷组

[root@localhost ~]# pvdisplay
  --- Physical volume ---
  PV Name               /dev/sda2
  VG Name               VolGroup
  PV Size               19.51 GiB / not usable 3.00 MiB
  Allocatable           yes (but full)
  PE Size               4.00 MiB
  Total PE              4994
  Free PE               0
  Allocated PE          4994
  PV UUID               qkBdcn-RQaR-ZliO-Ja2S-RhMC-stw8-CO213I

  "/dev/sdb1" is a new physical volume of "19.99 GiB"
  --- NEW Physical volume ---
  PV Name               /dev/sdb1
  VG Name
  PV Size               19.99 GiB
  Allocatable           NO
  PE Size               0
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               H7tDqG-6AZv-yBSA-U0ov-Ni0y-dlPA-kAA83i

[root@localhost ~]# vgextend VolGroup /dev/sdb1
  Volume group "VolGroup" successfully extended
You have new mail in /var/spool/mail/root
[root@localhost ~]# vgdisplay
  --- Volume group ---
  VG Name               VolGroup
  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               39.50 GiB
  PE Size               4.00 MiB
  Total PE              10112
  Alloc PE / Size       4994 / 19.51 GiB
  Free  PE / Size       5118 / 19.99 GiB
  VG UUID               dc0vI9-KzGu-4S59-A1xv-NM4Y-rYBF-3jDNRn

5、扩展逻辑卷

[root@localhost ~]# lvextend -l +100%free /dev/mapper/VolGroup-lv_root
#free也可以大写FREE
  Extending logical volume lv_root to 37.50 GiB
  Logical volume lv_root successfully resized
[root@localhost ~]# blkid /dev/mapper/VolGroup-lv_root
#查看分区文件系统类型
/dev/mapper/VolGroup-lv_root: UUID="972fdddd-ddb8-469f-a342-e075eaeabeb2" TYPE="ext4"
[root@localhost ~]# e2fsck -f /dev/mapper/VolGroup-lv_root
#e2fsck -f检查分区
e2fsck 1.41.12 (17-May-2010)
/dev/mapper/VolGroup-lv_root is mounted.
e2fsck: Cannot continue, aborting.

[root@localhost ~]# resize2fs /dev/mapper/VolGroup-lv_root
#如果分区是xfs系统，则用xfs_growfs命令对文件系统进行扩展
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/mapper/VolGroup-lv_root is mounted on /; on-line resizing required
old desc_blocks = 2, new_desc_blocks = 3
Performing an on-line resize of /dev/mapper/VolGroup-lv_root to 9830400 (4k) blocks.
The filesystem on /dev/mapper/VolGroup-lv_root is now 9830400 blocks long.

[root@localhost ~]# df -h
#查看磁盘空间，根分区已扩展到37G。
Filesystem                    Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root   37G  7.0G   29G  20% /
tmpfs                         2.0G  224K  2.0G   1% /dev/shm
/dev/sda1                     485M   40M  421M   9% /boot
/dev/sr0                      3.6G  3.6G     0 100% /media/cdrom