因为linux使用了lvm进行磁盘空间的组织与管理，有些类似于raid0。
磁盘空间在使用上直接面对的是逻辑卷，而逻辑卷则又使用卷组管理物理卷，物理卷就是直接创建在物理磁盘上的空间。
所以除了系统文件所在的根目录之外，所有挂载的数据目录都是可以动态调整的，只要加入新的磁盘空间，就可以对逻辑卷进行缩放。
磁盘扩容 - 图1
而系统所在的根目录，理论上只能扩容，无法进行缩容，因为磁盘空间一旦加入进去就被完全占用了，无法释放。

Step.1 物理磁盘分区

先查看系统上安装的磁盘情况。

  1. [root@0001 server1]# df -h
  2. Filesystem               Size  Used Avail Use% Mounted on
  3. /dev/mapper/centos-root   50G   46G  4.5G  92% /
  4. devtmpfs                  16G     0   16G   0% /dev
  5. tmpfs                     16G     0   16G   0% /dev/shm
  6. tmpfs                     16G  1.6G   15G  11% /run
  7. tmpfs                     16G     0   16G   0% /sys/fs/cgroup
  8. /dev/vda1               1014M  169M  846M  17% /boot
  9. /dev/mapper/centos-home   42G  324M   41G   1% /home
  10. tmpfs                    3.2G     0  3.2G   0% /run/user/1001
  11. tmpfs                    3.2G     0  3.2G   0% /run/user/1003
  12. tmpfs                    3.2G     0  3.2G   0% /run/user/0
  14. [root@0001 server1]# fdisk -l
  16. Disk /dev/vda: 107.4 GB, 107374182400 bytes, 209715200 sectors
  17. Units = sectors of 1 * 512 = 512 bytes
  18. Sector size (logical/physical): 512 bytes / 512 bytes
  19. I/O size (minimum/optimal): 512 bytes / 512 bytes
  20. Disk label type: dos
  21. Disk identifier: 0x000d5b31
  23.    Device Boot      Start         End      Blocks   Id  System
  24. /dev/vda1   *        2048     2099199     1048576   83  Linux
  25. /dev/vda2         2099200   209715199   103808000   8e  Linux LVM
  27. Disk /dev/vdb: 107.4 GB, 107374182400 bytes, 209715200 sectors
  28. Units = sectors of 1 * 512 = 512 bytes
  29. Sector size (logical/physical): 512 bytes / 512 bytes
  30. I/O size (minimum/optimal): 512 bytes / 512 bytes
  33. Disk /dev/mapper/centos-root: 53.7 GB, 53687091200 bytes, 104857600 sectors
  34. Units = sectors of 1 * 512 = 512 bytes
  35. Sector size (logical/physical): 512 bytes / 512 bytes
  36. I/O size (minimum/optimal): 512 bytes / 512 bytes
  39. Disk /dev/mapper/centos-swap: 8455 MB, 8455716864 bytes, 16515072 sectors
  40. Units = sectors of 1 * 512 = 512 bytes
  41. Sector size (logical/physical): 512 bytes / 512 bytes
  42. I/O size (minimum/optimal): 512 bytes / 512 bytes
  45. Disk /dev/mapper/centos-home: 44.1 GB, 44149243904 bytes, 86228992 sectors
  46. Units = sectors of 1 * 512 = 512 bytes
  47. Sector size (logical/physical): 512 bytes / 512 bytes
  48. I/O size (minimum/optimal): 512 bytes / 512 bytes

发现有一块磁盘 /dev/vdb 没有使用。接下来对物理磁盘进行格式化与分区。

  1. [root@0001 server1]# fdisk /dev/vdb
  2. Welcome to fdisk (util-linux 2.23.2).
  4. Changes will remain in memory only, until you decide to write them.
  5. Be careful before using the write command.
  7. Device does not contain a recognized partition table
  8. Building a new DOS disklabel with disk identifier 0xea2ef8f6.
  10. Command (m for help): n
  11. Partition type:
  12.    p   primary (0 primary, 0 extended, 4 free)
  13.    e   extended
  14. Select (default p): 
  16. Using default response p
  17. Partition number (1-4, default 1): First sector (2048-209715199, default 2048): 
  19. Using default value 2048
  20. Last sector, +sectors or +size{K,M,G} (2048-209715199, default 209715199): Using default value 209715199
  21. Partition 1 of type Linux and of size 100 GiB is set
  23. Command (m for help): t
  24. Selected partition 1
  25. Hex code (type L to list all codes): 8e
  26. Changed type of partition 'Linux' to 'Linux LVM'
  28. Command (m for help): w
  29. The partition table has been altered!
  31. Calling ioctl() to re-read partition table.
  32. Syncing disks.

Step.2 操作LVM

  1. [root@0001 server1]# fdisk -l
  3. Disk /dev/vda: 107.4 GB, 107374182400 bytes, 209715200 sectors
  4. Units = sectors of 1 * 512 = 512 bytes
  5. Sector size (logical/physical): 512 bytes / 512 bytes
  6. I/O size (minimum/optimal): 512 bytes / 512 bytes
  7. Disk label type: dos
  8. Disk identifier: 0x000d5b31
  10.    Device Boot      Start         End      Blocks   Id  System
  11. /dev/vda1   *        2048     2099199     1048576   83  Linux
  12. /dev/vda2         2099200   209715199   103808000   8e  Linux LVM
  14. Disk /dev/vdb: 107.4 GB, 107374182400 bytes, 209715200 sectors
  15. Units = sectors of 1 * 512 = 512 bytes
  16. Sector size (logical/physical): 512 bytes / 512 bytes
  17. I/O size (minimum/optimal): 512 bytes / 512 bytes
  18. Disk label type: dos
  19. Disk identifier: 0xea2ef8f6
  21.    Device Boot      Start         End      Blocks   Id  System
  22. /dev/vdb1            2048   209715199   104856576   8e  Linux LVM
  24. Disk /dev/mapper/centos-root: 53.7 GB, 53687091200 bytes, 104857600 sectors
  25. Units = sectors of 1 * 512 = 512 bytes
  26. Sector size (logical/physical): 512 bytes / 512 bytes
  27. I/O size (minimum/optimal): 512 bytes / 512 bytes
  30. Disk /dev/mapper/centos-swap: 8455 MB, 8455716864 bytes, 16515072 sectors
  31. Units = sectors of 1 * 512 = 512 bytes
  32. Sector size (logical/physical): 512 bytes / 512 bytes
  33. I/O size (minimum/optimal): 512 bytes / 512 bytes
  36. Disk /dev/mapper/centos-home: 44.1 GB, 44149243904 bytes, 86228992 sectors
  37. Units = sectors of 1 * 512 = 512 bytes
  38. Sector size (logical/physical): 512 bytes / 512 bytes
  39. I/O size (minimum/optimal): 512 bytes / 512 bytes
  41. [root@0001 server1]# pvcreate /dev/vdb1
  42.   Physical volume "/dev/vdb1" successfully created.
  43. [root@0001 server1]# pvdisplay
  44.   --- Physical volume ---
  45.   PV Name               /dev/vda2
  46.   VG Name               centos
  47.   PV Size               <99.00 GiB / not usable 3.00 MiB
  48.   Allocatable           yes 
  49.   PE Size               4.00 MiB
  50.   Total PE              25343
  51.   Free PE               1
  52.   Allocated PE          25342
  53.   PV UUID               D3atmG-vYwp-asY9-UCMy-L5LZ-JgH6-CrYXdl
  55.   "/dev/vdb1" is a new physical volume of "<100.00 GiB"
  56.   --- NEW Physical volume ---
  57.   PV Name               /dev/vdb1
  58.   VG Name               
  59.   PV Size               <100.00 GiB
  60.   Allocatable           NO
  61.   PE Size               0   
  62.   Total PE              0
  63.   Free PE               0
  64.   Allocated PE          0
  65.   PV UUID               BSpZvK-jM8r-fYDo-XsuS-huoa-NMsd-EdnSSw
  67. [root@0001 server1]# vgdisplay 
  68.   --- Volume group ---
  69.   VG Name               centos
  70.   System ID             
  71.   Format                lvm2
  72.   Metadata Areas        1
  73.   Metadata Sequence No  4
  74.   VG Access             read/write
  75.   VG Status             resizable
  76.   MAX LV                0
  77.   Cur LV                3
  78.   Open LV               3
  79.   Max PV                0
  80.   Cur PV                1
  81.   Act PV                1
  82.   VG Size               <99.00 GiB
  83.   PE Size               4.00 MiB
  84.   Total PE              25343
  85.   Alloc PE / Size       25342 / 98.99 GiB
  86.   Free  PE / Size       1 / 4.00 MiB
  87.   VG UUID               kZrifW-oQKr-6ezp-J1fz-l704-BHCs-QZhIRq
  89. [root@0001 server1]# vgextend centos /dev/vdb1
  90.   Volume group "centos" successfully extended
  91. [root@0001 server1]# vgdisplay 
  92.   --- Volume group ---
  93.   VG Name               centos
  94.   System ID             
  95.   Format                lvm2
  96.   Metadata Areas        2
  97.   Metadata Sequence No  5
  98.   VG Access             read/write
  99.   VG Status             resizable
  100.   MAX LV                0
  101.   Cur LV                3
  102.   Open LV               3
  103.   Max PV                0
  104.   Cur PV                2
  105.   Act PV                2
  106.   VG Size               198.99 GiB
  107.   PE Size               4.00 MiB
  108.   Total PE              50942
  109.   Alloc PE / Size       25342 / 98.99 GiB
  110.   Free  PE / Size       25600 / 100.00 GiB
  111.   VG UUID               kZrifW-oQKr-6ezp-J1fz-l704-BHCs-QZhIRq
  113. [root@0001 server1]# lvextend -l +100%FREE /dev/mapper/centos-root /dev/vdb1
  114.   Size of logical volume centos/root changed from 50.00 GiB (12800 extents) to <150.00 GiB (38399 extents).
  115.   Logical volume centos/root successfully resized.
  116. [root@0001 server1]# xfs_growfs /dev/mapper/centos-root 
  117. meta-data=/dev/mapper/centos-root isize=512    agcount=4, agsize=3276800 blks
  118.          =                       sectsz=512   attr=2, projid32bit=1
  119.          =                       crc=1        finobt=0 spinodes=0
  120. data     =                       bsize=4096   blocks=13107200, imaxpct=25
  121.          =                       sunit=0      swidth=0 blks
  122. naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
  123. log      =internal               bsize=4096   blocks=6400, version=2
  124.          =                       sectsz=512   sunit=0 blks, lazy-count=1
  125. realtime =none                   extsz=4096   blocks=0, rtextents=0
  126. data blocks changed from 13107200 to 39320576
  127. [root@0001 server1]# df -h
  128. Filesystem               Size  Used Avail Use% Mounted on
  129. /dev/mapper/centos-root  150G   46G  105G  31% /
  130. devtmpfs                  16G     0   16G   0% /dev
  131. tmpfs                     16G     0   16G   0% /dev/shm
  132. tmpfs                     16G  1.6G   15G  11% /run
  133. tmpfs                     16G     0   16G   0% /sys/fs/cgroup
  134. /dev/vda1               1014M  169M  846M  17% /boot
  135. /dev/mapper/centos-home   42G  324M   41G   1% /home
  136. tmpfs                    3.2G     0  3.2G   0% /run/user/1001
  137. tmpfs                    3.2G     0  3.2G   0% /run/user/1003
  138. tmpfs                    3.2G     0  3.2G   0% /run/user/0