Linux下磁盘管理

一、索引式文件系统特性
sector：最小物理存储单位，

superblock：记录整个文件系统的信息，包括inode、block总量、使用量、剩余量及文件系统格式等信息；

inode：记录文件属性，并指向文件实际存储的blokck号；

block：存储文件内容，一个block只能存储同一个文件的内容，block的大小好比往圆柱体里放正方体，正方体越小则放得越多，但存取速度也越慢；

二、磁盘管理
一）、查看磁盘及分区情况

[root@a ~]# lsblk
NAME              MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda                 8:0    0   20G  0 disk
├─sda1              8:1    0    2M  0 part
├─sda2              8:2    0  500M  0 part /boot
└─sda3              8:3    0 19.5G  0 part
├─centos_a-root 253:0    0   10G  0 lvm  /
├─centos_a-swap 253:1    0    1G  0 lvm  [SWAP]
└─centos_a-home 253:2    0  8.5G  0 lvm  /home
sr0                11:0    1 1024M  0 rom
[root@a ~]# parted /dev/sda print   ###查看分割表
Model: VMware, VMware Virtual S (scsi)
Disk /dev/sda: 21.5GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:

Number  Start   End     Size    Type     File system  Flags
1      1049kB  3146kB  2097kB  primary
2      3146kB  527MB   524MB   primary  xfs          boot
3      527MB   21.5GB  20.9GB  primary               lvm

二）、磁盘分割

MBR使用fdisk，GPT使用gdisk，它们使用基本一样。分割一个5M的分区

[root@a ~]# fidsk /dev/sda
bash: fidsk: command not found...
Similar command is: 'fdisk'
[root@a ~]# fdisk /dev/sda
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): n    ##新建一个分区
Partition type:
p   primary (3 primary, 0 extended, 1 free)
e   extended
Select (default e):   ##msdos最多只能有4个分区，所以建立扩展分区
Using default response e
Selected partition 4
First sector (41934848-41943039, default 41934848): ##默认即可
Using default value 41934848                            ##↓输入分区大小
Last sector, +sectors or +size{K,M,G} (41934848-41943039, default 41943039): +10M
Value out of range.
Last sector, +sectors or +size{K,M,G} (41934848-41943039, default 41943039):
Using default value 41943039
Partition 4 of type Extended and of size 4 MiB is set

Command (m for help): p  ##查看分区

Disk /dev/sda: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x0007947d

Device Boot      Start         End      Blocks   Id  System
/dev/sda1            2048        6143        2048   83  Linux
/dev/sda2   *        6144     1030143      512000   83  Linux
/dev/sda3         1030144    41934847    20452352   8e  Linux LVM
/dev/sda4        41934848    41943039        4096    5  Extended

Command (m for help): w  ###写入分区表
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@a ~]# partprobe -s   ##更新分区表
/dev/sda: msdos partitions 1 2 3 4 <>

三）、格式化分区

[root@a ~]# mkfs.   ##格式化类型
mkfs.btrfs   mkfs.ext2    mkfs.ext4    mkfs.minix   mkfs.vfat
mkfs.cramfs  mkfs.ext3    mkfs.fat     mkfs.msdos   mkfs.xfs
[root@a ~]# mkfs.ext4 /dev/sda4   ##可以使用-d指定block大小
mke2fs 1.42.9 (28-Dec-2013)
mkfs.ext4: inode_size (128) * inodes_count (0) too big for a
filesystem with 0 blocks, specify higher inode_ratio (-i)
or lower inode count (-N).

四）、挂载

[root@a ~]# mount /dev/sda4 /ui  ##挂载到目录
[root@a ~]# vim /etc/fstab   ##追加，开机挂载
/dev/sda4                 /fl                     etx4    defaults        0 0