Linux磁盘分区介绍

磁盘分区介绍

一、fdisk命令介绍
1)、fdisk -l 查看本机磁盘信息(查的本机有两块硬盘，分别是sda 128.8G，sdb21.5G，sda这块硬盘有两个分区，分别是sda1，sda2)

[root@station78 ~]# fdisk -l
Disk /dev/sda: 128.8 GB, 128849018880 bytes
255 heads, 63 sectors/track, 15665 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: 0x00057501
Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          26      204800   83  Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2              26        7859    62914560   8e  Linux LVM
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: 0x12ae388b
Device Boot      Start         End      Blocks   Id  System

2）、对/dev/sdb这块硬盘进行基本操作




3)、创建分区，查看分区，保存分区信息并退出（设置一个5G的主分区）

[root@station78 ~]# fdisk  /dev/sdb
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): n
Command action
e   extended
p   primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-2610, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-2610, default 2610): +5G
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: 0x12ae388b
Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1         654     5253223+  83  Linux
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
[root@station78 ~]# fdisk -l /dev/sdb
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: 0x12ae388b
Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1         654     5253223+  83  Linux
[root@station78 ~]#

4）、磁盘分区之后，使用的内核读到硬盘分区信息然后才能格式化分区（让内核重新读取硬盘的分区数）使用以下命令查看是否出现了sdb1的信息，从一下结构中很容易得知内核已经读到了硬盘信息

[root@station78 ~]# cat /proc/partitions
major minor  #blocks  name
8        0  125829120 sda
8        1     204800 sda1
8        2   62914560 sda2
8       16   20971520 sdb
8       17    5253223 sdb1
253        0   20971520 dm-0
253        1    2097152 dm-1
253        2   10485760 dm-2
253        3   20971520 dm-3
[root@station78 ~]#

注意：如果内核没有读取信息，则使用以下命令,然后在查看

[root@station78 ~]# partx  -a /dev/sdb1 /dev/sdb
[root@station78 ~]#

二、硬盘的格式化查看磁盘类型并修改块大小
1）、使用mkfs 命令格式化硬盘

[root@station78 ~]# mkfs -t ext4 /dev/sdb1
mke2fs 1.41.12 (17-May-2010)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
328656 inodes, 1313305 blocks
65665 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=1346371584
41 block groups
32768 blocks per group, 32768 fragments per group
8016 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 30 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.
[root@station78 ~]#

2)、查看文件类型以及分区的唯一标识UUID（UUID用于区分硬盘）

[root@station78 ~]# blkid /dev/sdb1
/dev/sdb1: UUID="f2263aef-fbc0-4dab-abc1-ccda473dc20a" TYPE="ext4"
[root@station78 ~]#

3）、修改硬盘的块大小，默认的块大小是4096字节，如果我们存储的数据文件都是小文件的时候，那么我们需要将块调小一些，这样更加合理的利用磁盘空间

mke2fs 不仅可以修改块大小，还能够设置磁盘的类型，设定卷标等

Mke2fs 命令常用选项
-b {1024|2048|4096 } bytes   设置块大小
-t {ext2|ext3|ext4}           指定文件类型
-L    指定卷标

4）使用mke2fs 设定/dev/sdb1的文件类型，块大小并指定卷标

[root@station78 ~]# mke2fs -t ext4 -b 1024 -L MYDAT /dev/sdb1
mke2fs 1.41.12 (17-May-2010)
Filesystem label=MYDAT
OS type: Linux
Block size=1024 (log=0)
Fragment size=1024 (log=0)
Stride=0 blocks, Stripe width=0 blocks
328704 inodes, 5253220 blocks
262661 blocks (5.00%) reserved for the super user
First data block=1
Maximum filesystem blocks=72613888
642 block groups
8192 blocks per group, 8192 fragments per group
512 inodes per group
Superblock backups stored on blocks:
8193, 24577, 40961, 57345, 73729, 204801, 221185, 401409, 663553,
1024001, 1990657, 2809857, 5120001
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 27 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.
[root@station78 ~]#

5)、查看硬盘信息

[root@station78 ~]# blkid /dev/sdb1
/dev/sdb1: UUID="4bc881bb-8e96-4c10-9541-1169b01f28e5" TYPE="ext4" LABEL="MYDAT"
[root@station78 ~]#

注意：设定硬盘块大小时候必须格式化硬盘
三、硬盘格式化之后查看硬盘属性并调整（使用 tune2fs 命令）
1）、查看设备属性

[root@station78 ~]# tune2fs -l /dev/sdb1
tune2fs 1.41.12 (17-May-2010)
Filesystem volume name:   MYDAT
Last mounted on:          <not available>
Filesystem UUID:          4bc881bb-8e96-4c10-9541-1169b01f28e5
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal ext_attr resize_inode dir_index filetype extent flex_bg sparse_super huge_file uninit_bg dir_nlink extra_isize
Filesystem flags:         signed_directory_hash
Default mount options:    (none)
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              328704
Block count:              5253220
Reserved block count:     262661
Free blocks:              5133085
Free inodes:              328693
First block:              1
Block size:               1024
Fragment size:            1024
Reserved GDT blocks:      256
Blocks per group:         8192
Fragments per group:      8192
Inodes per group:         512
Inode blocks per group:   128
Flex block group size:    16
Filesystem created:       Wed Jul 17 07:33:29 2013
Last mount time:          n/a
Last write time:          Wed Jul 17 07:33:31 2013
Mount count:              0
Maximum mount count:      27
Last checked:             Wed Jul 17 07:33:29 2013
Check interval:           15552000 (6 months)
Next check after:         Mon Jan 13 07:33:29 2014
Lifetime writes:          113 MB
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:           256
Required extra isize:     28
Desired extra isize:      28
Journal inode:            8
Default directory hash:   half_md4
Directory Hash Seed:      16ed53d0-29bf-4fd8-b50e-d98a5d87984b
Journal backup:           inode blocks
[root@station78 ~]#shan

2）、通过硬盘属性查看硬盘预留空间的块数（设置预留空间的块数的原因是防止硬盘数据存满以后，管理员无法在硬盘中任何操作，比如说当硬盘数据100%的时候，管理员无法使用任何命令操作。）

[root@station78 ~]# tune2fs -l /dev/sdb1 | grep "Reserved"
Reserved block count:     262661                  块数
Reserved GDT blocks:      256
Reserved blocks uid:      0 (user root)          管理员
Reserved blocks gid:      0 (group root)
[root@station78 ~]#

3）、调整预留空间的块大小（防止当硬盘分区较大时浪费磁盘容量）

[root@station78 ~]# tune2fs -m 3 /dev/sdb1   设置预留块数为3%
tune2fs 1.41.12 (17-May-2010)
Setting reserved blocks percentage to 3% (157596 blocks)
[root@station78 ~]# tune2fs -l /dev/sdb1 | grep "Reserved" 查看属性
Reserved block count:     157596                       变成157596
Reserved GDT blocks:      256
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
[root@station78 ~]#

四、硬盘的挂载和卸载
1)、挂载与卸载