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
