centos的 df命令 centos dd

转载

mob6454cc79ab13 2024-04-25 11:07:00

文章标签 centos的 df命令 centos 根分区扩容 linux 文章分类 架构后端开发

操作环境：
[root@linuxidc ~]# uname -a
Linux linuxidc 2.6.32-358.18.1.el6.x86_64#1 SMP Wed Aug 28 17:19:38 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
现状分析：
系统有两个硬盘，第一个硬盘107G,“/”分区空间当时分区时只给了7.7G过小，空间马上占完。现在系统有第二个硬盘sdb大小为16GB，希望把sdb的所有空间加入到“/”分区中，是其空间容量从7.7GB变成7.7GB+16GB（约2.4GB）。（当然如果这里只有一个硬盘sda,有很多空间尚未使用可以进行同样的操作）
操作步骤如下：
第一步、查看本机现有分区情况
[root@linuxidc ~]# df -h
文件系统容量已用可用已用%% 挂载点

/dev/mapper/VolGroup-lv_root
                     7.7G  7.1G 155M  98% /
 tmpfs                3.9G  296K 3.9G  1% /dev/shm
 /dev/sda1            485M  64M 396M  14% /boot
 /dev/sda3              83G  350M  79G  1% /media

第二步、查看本机的磁盘情况

[root@linuxidc ~]# fdisk -l
 
 Disk /dev/sda: 107.4 GB, 107374182400 bytes
 255 heads, 63 sectors/track, 13054cylinders
 Units = cylinders of 16065 * 512 = 8225280bytes
 Sector size (logical/physical): 512 bytes /512 bytes
 I/O size (minimum/optimal): 512 bytes / 512bytes
 Disk identifier: 0x000dc0ad 
  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        2089  16264192  8e  Linux LVM
 /dev/sda3            2090      13054  88076362+  83  Linux 
 Disk /dev/mapper/VolGroup-lv_root: 8325 MB,8325693440 bytes
 255 heads, 63 sectors/track, 1012 cylinders
 Units = cylinders of 16065 * 512 = 8225280bytes
 Sector size (logical/physical): 512 bytes /512 bytes
 I/O size (minimum/optimal): 512 bytes / 512bytes
 Disk identifier: 0x00000000  
 
 Disk /dev/mapper/VolGroup-lv_swap: 8325 MB,8325693440 bytes
 255 heads, 63 sectors/track, 1012 cylinders
 Units = cylinders of 16065 * 512 = 8225280bytes
 Sector size (logical/physical): 512 bytes /512 bytes
 I/O size (minimum/optimal): 512 bytes / 512bytes
 Disk identifier: 0x00000000

注意：此时还没有在EXSI5.0中添加第二块硬盘
[root@linuxidc ~]#
第三步、添加第二块硬盘

查看此时系统磁盘情况

root@linuxidc ~]# fdisk -l
 
 Disk /dev/sda: 107.4 GB, 107374182400 bytes
 255 heads, 63 sectors/track, 13054cylinders
 Units = cylinders of 16065 * 512 = 8225280bytes
 Sector size (logical/physical): 512 bytes /512 bytes
 I/O size (minimum/optimal): 512 bytes / 512bytes
 Disk identifier: 0x000dc0ad 
  Device Boot      Start        End      Blocks  Id  System
 /dev/sda1  *          1          64      512000  83  Linux
 Partition 1 does not end on cylinderboundary.
 /dev/sda2              64        2089  16264192  8e  Linux LVM
 /dev/sda3            2090      13054  88076362+  83  Linux 
 Disk /dev/sdb: 17.2 GB, 17179869184 bytes
 255 heads, 63 sectors/track, 2088 cylinders
 Units = cylinders of 16065 * 512 = 8225280bytes
 Sector size (logical/physical): 512 bytes /512 bytes
 I/O size (minimum/optimal): 512 bytes / 512bytes
 Disk identifier: 0x00000000  
 
 Disk /dev/mapper/VolGroup-lv_root: 8325 MB,8325693440 bytes
 255 heads, 63 sectors/track, 1012 cylinders
 Units = cylinders of 16065 * 512 = 8225280bytes
 Sector size (logical/physical): 512 bytes /512 bytes
 I/O size (minimum/optimal): 512 bytes / 512bytes
 Disk identifier: 0x00000000  
 
 Disk /dev/mapper/VolGroup-lv_swap: 8325 MB,8325693440 bytes
 255 heads, 63 sectors/track, 1012 cylinders
 Units = cylinders of 16065 * 512 = 8225280bytes
 Sector size (logical/physical): 512 bytes /512 bytes
 I/O size (minimum/optimal): 512 bytes / 512bytes
 Disk identifier: 0x00000000

可以看到我们新添加的硬盘sdb

[root@linuxidc ~]#
第四步、对第二块硬盘sdb进行分区

[root@linuxidc ~]# fdisk /dev/sdb
 Device contains neither a valid DOSpartition table, nor Sun, SGI or OSF disklabel
 Building a new DOS disklabel with diskidentifier 0xfa4abbdc.
 Changes will remain in memory only, untilyou decide to write them.
 After that, of course, the previous contentwon't be recoverable. 
 Warning: invalid flag 0x0000 of partitiontable 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): m
 Command action
  a  toggle a bootable flag
  b  edit bsd disklabel
  c  toggle the dos compatibilityflag
  d  delete a partition
  l  list known partition types
  m  print this menu
  n  add a new partition
  o  create a new empty DOSpartition table
  p  print the partition table
  q  quit without saving changes
  s  create a new empty Sundisklabel
  t  change a partition's system id
  u  change display/entry units
  v  verify the partition table
  w  write table to disk and exit
  x  extra functionality (expertsonly) 
 Command (m for help): n
 Command action
  e  extended
  p  primary partition (1-4)
 p  
 Partition number (1-4): 4
 First cylinder (1-2088, default 1): 
 Using default value 1
 Last cylinder, +cylinders or +size{K,M,G}(1-2088, default 2088): 
 Using default value 2088 
 Command (m for help): w
 The partition table has been altered! 
 Calling ioctl() to re-read partition table.
 Syncing disks.

说明：上面操作对sdb硬盘进行了分区操作，设为sdb4分区了（当然上面建立的主分区可以为1-4中的任意一个，我这里选择的4）。

第五步、对新建立的sdb4分区进行格式

[root@linuxidc ~]# mkfs.ext4 /dev/sdb4
 mke2fs 1.41.12 (17-May-2010)
 文件系统标签=
 操作系统:Linux
 块大小=4096 (log=2)
 分块大小=4096 (log=2)
 Stride=0 blocks, Stripe width=0 blocks
 1048576 inodes, 4192957 blocks
 209647 blocks (5.00%) reserved for thesuper user
 第一个数据块=0
 Maximum filesystem blocks=4294967296
 128 block groups
 32768 blocks per group, 32768 fragments pergroup
 8192 inodes per group
 Superblock backups stored on blocks: 
       32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
       4096000

正在写入inode表: 完成

Creating journal (32768 blocks): 完成
 Writing superblocks and filesystemaccounting information: done完成 
 This filesystem will be automaticallychecked every 20 mounts or
 180 days, whichever comes first.  Use tune2fs -c or -i to override.

说明：将sdb4分区格式化为ext4格式，因为CentOS安装是系统的格式ext4，所以这里要注意一下。

第六步、格式后的sdb4分区添加为物理卷

[root@linuxidc ~]# pvcreate /dev/sdb4
 Physical volume "/dev/sdb4" successfully created

第七步、查看当前系统的物理卷（PV）情况

[root@linuxidc ~]# pvdisplay
 ---Physical volume ---
 PVName /dev/sda2
 VGName VolGroup
 PVSize 15.51 GiB / not usable3.00 MiB
 Allocatable yes (butfull)
 PESize 4.00 MiB
 Total PE 3970
 Free PE 0
 Allocated PE 3970
 PVUUID Up77sG-sNKf-Ja0k-crBf-N0wz-a5hy-T6sVFh 
 "/dev/sdb4" is a new physical volume of "15.99 GiB"
 ---NEW Physical volume ---
 PVName /dev/sdb4
 VGName 
 PVSize 15.99 GiB
 Allocatable NO
 PESize 0 
 Total PE 0
 Free PE 0
 Allocated PE 0
 PVUUID Gqnw7N-HooX-S2Nz-1NIZ-YpOe-g0jo-grG1rQ

说明：可以看到添加的新物理卷sdb4，大小都符合我们添加时的设置

第八步、查看当前卷组情况

[root@linuxidc ~]# vgdisplay
 ---Volume group ---
 VGName VolGroup
 System ID 
 Format lvm2
 Metadata Areas 1
 Metadata Sequence No 3
 VGAccess read/write
 VGStatus resizable
 MAXLV 0
 CurLV 2
 Open LV 2
 MaxPV 0
 CurPV 1
 ActPV 1
 VGSize 15.51 GiB
 PESize 4.00 MiB
 Total PE 3970
 Alloc PE / Size 3970 / 15.51GiB
 Free PE / Size 0 / 0 
 VGUUID PPrifh-glzl-nnxX-YkBm-xJ1s-rgnw-d1WsJd

第九步、将分区sdb4转换为扩展分区

[root@linuxidc ~]# vgextend VolGroup/dev/sdb4
 Volume group "VolGroup" successfully extended

第十步、查看当前的逻辑卷

[root@linuxidc ~]# lvdisplay
 ---Logical volume ---
 LVPath /dev/VolGroup/lv_root
 LVName lv_root
 VGName VolGroup
 LVUUID dCIsej-0NWX-bVFe-bT6L-c4eY-oy4G-9lNBOC
 LVWrite Access read/write
 LVCreation host, time , 
 LVStatus available
 #open 1
 LVSize 7.75 GiB
 Current LE 1985
 Segments 1
 Allocation inherit
 Read ahead sectors auto
 -currently set to 256
 Block device 253:0 
 ---Logical volume ---
 LVPath /dev/VolGroup/lv_swap
 LVName lv_swap
 VGName VolGroup
 LVUUID K5bxJo-2SmM-6NCU-mBJP-Qzp1-ZODH-nbLK0k
 LVWrite Access read/write
 LVCreation host, time , 
 LVStatus available
 #open 1
 LVSize 7.75 GiB
 Current LE 1985
 Segments 1
 Allocation inherit
 Read ahead sectors auto
 -currently set to 256
 Block device 253:1

说明：这里可以看到“/”根分区的路径名称为：/dev/VolGroup/lv_root

第十一步、查看扩展后的卷组情况

[root@linuxidc ~]# vgdisplay
 ---Volume group ---
 VGName VolGroup
 System ID 
 Format lvm2
 Metadata Areas 2
 Metadata Sequence No 4
 VGAccess read/write
 VGStatus resizable
 MAXLV 0
 CurLV 2
 Open LV 2
 MaxPV 0
 CurPV 2
 ActPV 2
 VGSize 31.50 GiB
 PESize 4.00 MiB
 Total PE 8064
 Alloc PE / Size 3970 / 15.51GiB
 Free PE / Size 4094 / 15.99 GiB
 VGUUID PPrifh-glzl-nnxX-YkBm-xJ1s-rgnw-d1WsJd

说明：扩展后的卷子情况，可以看出大小增加了16GB（与第八步中的对比）

第十二步、将新增的逻辑卷全部扩展到“/”分区中

[root@linuxidc ~]# lvextend -L +15.99G/dev/VolGroup/lv_root 
 Rounding size to boundary between physical extents: 15.99 GiB
 Extending logical volume lv_root to 23.75 GiB
 Logical volume lv_root successfully resized

说明：这里sdb4总共有16G，所以把16BG全部添加给根分区。

第十三步、查看“/”根分区格式，并重新刷新根分区的大小

[root@linuxidc ~]# e2fsck -f/dev/VolGroup/lv_root 
 e2fsck 1.41.12 (17-May-2010)
 /dev/VolGroup/lv_root is mounted.
 e2fsck: 无法继续, 中止. 
 [root@linuxidc ~]# resize2fs /dev/VolGroup/lv_root 
 resize2fs 1.41.12 (17-May-2010)
 Filesystem at /dev/VolGroup/lv_root ismounted on /; on-line resizing required
 old desc_blocks = 1, new_desc_blocks = 2
 Performing an on-line resize of/dev/VolGroup/lv_root to 6224896 (4k) blocks.
 The filesystem on /dev/VolGroup/lv_root isnow 6224896 blocks long.

说明：命令resize2fs即刷新根分区“/dev/VolGroup/lv_root”的容量。

第十三步、查看刷新后根分区的大小

[root@linuxidc ~]# df -h
 文件系统容量已用可用已用%% 挂载点
 /dev/mapper/VolGroup-lv_root
 24G 7.1G 16G 32% /
 tmpfs 3.9G 144K 3.9G 1% /dev/shm
 /dev/sda3 83G 350M 79G 1% /media/Lucene

说明：可以看到根分区的大小有7.7G变成了24G，重启一下系统再来看情况。此时就可以继续安装软件了，不会提示空间不足了。

本文章为转载内容，我们尊重原作者对文章享有的著作权。如有内容错误或侵权问题，欢迎原作者联系我们进行内容更正或删除文章。