管理分区
查看系统中的分区4种方式
[root@localhost ~]# ls /dev/sd* [来自内存]
[root@localhost ~]# cat /proc/partitions
[root@localhost ~]# lsblk
/dev/sda /dev/sda1 /dev/sda2 /dev/sda3 /dev/sda4 /dev/sda5
[root@localhost ~]# fdisk -l 看磁盘中的分区表
磁盘中的分区表可能和内存中的分区表是不同步的
parted命令
- parted的操作都是实时生效的，小心使用
- 用法：parted [选项]… [设备 [命令 [参数]…]…]
- parted /dev/sdb mklabel gpt|msdos
- parted /dev/sdb print
- parted /dev/sdb mkpart primary 1 200 （默认M）
- parted /dev/sdb rm 1
- parted -l
- mklabel gpt|msdos 用于指定创建的是GPT分区还是MBR分区
- 创建分区
[root@localhost app]# parted /dev/sdb mkpart primary 1 1000
Information: You may need to update /etc/fstab.
[root@localhost app]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 200G 0 disk
├─sda1 8:1 0 1G 0 part /boot
├─sda2 8:2 0 50G 0 part /
├─sda3 8:3 0 20G 0 part /app
├─sda4 8:4 0 1K 0 part
└─sda5 8:5 0 2G 0 part [SWAP]
sdb 8:16 0 20G 0 disk
└─sdb1 8:17 0 953M 0 part
GPT分区和MBR分区是互不兼容的，也不存在转换的问题，一旦设置了GPT分区或者MBR分区，要想装换只能重新分区
分区工具fdisk和gdisk
- gdisk /dev/sdb 类fdisk 的GPT分区工具
- fdisk -l [-u] [device…] 查看分区
- fdisk /dev/sdb 管理分区
- 子命令：
- p 分区列表
- t 更改分区类型
- n 创建新分区
- d 删除分区
- v 校验分区
- u 转换单位
- w 保存并退出
- q 不保存并退出
[root@localhost app]# gdisk /dev/sdb
GPT fdisk (gdisk) version 0.8.6
Partition table scan:
MBR: protective
BSD: not present
APM: not present
GPT: present
Found valid GPT with protective MBR; using GPT.
#gdisk的帮助信息
Command (? for help): ?
b back up GPT data to a file 备份GPT分区
c change a partition’s name 修改分区名
d delete a partition 删除分区
i show detailed information on a partition
l list known partition types
n add a new partition 添加一个新分区
o create a new empty GUID partition table (GPT) 创建一个GUID分区表
p print the partition table 打印分区表
q quit without saving changes不保存退出
r recovery and transformation options (experts only) 恢复修改的选项
s sort partitions 分区排序
t change a partition’s type code 修改分区类型代码
v verify disk 验证磁盘
w write table to disk and exit写入磁盘并且退出
x extra functionality (experts only) 扩展选项
? print this menu 打印出菜单
Command (? for help):
#把分区表转换为MBR类型
[root@localhost ~]# parted /dev/sdb mklabel msdos
Warning: The existing disk label on /dev/sdb will be destroyed and all data on this disk will be lost. Do
you want to continue?
Yes/No? yes
Information: You may need to update /etc/fstab.
[root@localhost ~]#
fdisk分区工具的使用
[root@localhost ~]# 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): m
Command action
a toggle a bootable flag
b edit bsd disklabel
c toggle the dos compatibility flag 不以dos兼容的模式
d delete a partition
g create a new empty GPT partition table
G create an IRIX (SGI) partition table
l list known partition types
m print this menu
n add a new partition
o create a new empty DOS partition table
p print the partition table
q quit without saving changes
s create a new empty Sun disklabel
t change a partition’s system id
u change display/entry units 以扇区为单位进行显示（单位为K）
v verify the partition table
w write table to disk and exit
x extra functionality (experts only)
Command (m for help):
在CentOS6中：
[root@localhost ~]# fdisk /dev/sda
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’).基于dos兼容模式是弃用。这是强烈推荐关掉模式(命令“c”)和改变显示单位部门(命令“u”)。也就是用传统的柱面的方式来划分去分区，并且要求以整柱面位单位进行划分，
Command (m for help): p
Disk /dev/sda: 214.7 GB, 214748364800 bytes
255 heads, 63 sectors/track, 26108 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: 0x0008cdd6
Device Boot Start End Blocks Id System
/dev/sda1 * 1 131 1048576 83 Linux
Partition 1 does not end on cylinder boundary. 默认以柱面为单位进行划分，不在整柱面上会提示
/dev/sda2 131 6658 52428800 83 Linux
/dev/sda3 6658 9269 20971520 83 Linux
/dev/sda4 9269 26109 135265280 5 Extended
/dev/sda5 9269 9530 2097152 82 Linux swap / Solaris
Command (m for help):
CentOS6默认以dos模式柱面为单位
CentOS7默认就是以非dos模式以扇区为单位，默认相当于已经加了c u 了，但也是可以改为以柱面为单位进行显示，例如打开的时候以柱面为单位进行显示
[root@localhost ~]# fdisk -h
Usage:
fdisk [options] <disk> change partition table
fdisk [options] -l <disk> list partition table(s)
fdisk -s <partition> give partition size(s) in blocks
Options:
-b <size> sector size (512, 1024, 2048 or 4096)
-c[=<mode>] compatible mode: ‘dos’ or ‘nondos’ (default)
-h print this help text
-u[=<unit>] display units: ‘cylinders’ or ‘sectors’ (default)
-v print program version
-C <number> specify the number of cylinders
-H <number> specify the number of heads
-S <number> specify the number of sectors per track
[root@localhost ~]# fdisk -u=cylinders /dev/sda
WARNING: cylinders as display units are deprecated. Use command ‘u’ to
change units to sectors.
Device Boot Start End Blocks Id System
/dev/sda1 * 1 131 1048576 83 Linux
/dev/sda5 9269 9530 2097152 82 Linux swap / Solaris
注意：注意不要在一个分区中的夹缝中分区，避免分出来的空间过小，或者分区的时候空间过大进行报错提示
Device Boot Start End Blocks Id System
/dev/sdc1 2048 8192 3072+ 83 Linux
/dev/sdc2 10240 62914559 31452160 83 Linux
Last sector, +sectors or +size{K,M,G} (8193-10239, default 10239): +10G
Value out of range.
分区不能调大调小，只能重头开始分区。例如删除分区6，分区7会变成分区6。
分区的标识、设备名是不稳定的，带来的问题就是将来在磁盘上进行分区配置文件的修改，写/sda5 sda6这样的名字，万一删掉了分区，设备名就变了，数据就找不到了配置文件就会出问题，不推荐写设备名称，分区完成后会生成UUID号，是唯一且不变的，建议写UUID号
在6中创建分区表同步失败
Command (m for help): n
First sector (148899903-419430399, default 148899903):
Using default value 148899903
Last sector, +sectors or +size{K,M,G} (148899903-148903935, default 148903935):
Using default value 148903935
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.
[root@localhost ~]#
需要手动同步分区表
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