df命令

Posted 2020-11-19 xiaoliangxianshen

CentOS7所支持的文件系统格式；默认是用xfs作为系统的文件系统。 "/"和"/boot"都是xfs格式！

[[email protected] ~]# cat /etc/filesystems

xfs

ext4

ext3

ext2

nodev proc

nodev devpts

iso9660

vfat

hfs

hfsplus

*

mke2fs命令：

mke2fs、mkfs.ext2、mkfs.ext3、mkfs.ext4均可用于磁盘格式化！唯独不支持xfs！

比如执行格式化为ext4系统(mkfs.ext4=mke2fs -t ext4)

  -L：=label，预设该分区的标签

  -t：用来指定文件系统的类型（xfs、ext4、ext3、ext2等）

  -b：分区时指定每个数据块的大小，目前支持1024、248、4096 bytes每个块

   -i：指定inode大小，默认单位是byte

  -N：设定inode数量，有时候默认的数量不够用，所以需要自己设定inode数量

   -c：在格式化之前先检测一下磁盘是否有问题，加上这个选项后会非常慢

  -m：格式化时，指定预留给管理员的磁盘比例，是一个百分比，只针对mke2fs命令

格式化sdb1为ext4文件系统

[[email protected] ~]# mke2fs -t ext4 -b 2048 /dev/sdb1#指定为ext4的格式，块大小为2048；这里还有一个命令mkfs.ext4等价于mke2fs -t ext4

mke2fs 1.42.9 (28-Dec-2013)

Filesystem label=

OS type: Linux

Block size=2048 (log=1)

Fragment size=2048 (log=1)

Stride=0 blocks, Stripe width=0 blocks

131072 inodes, 1048576 blocks

52428 blocks (5.00%) reserved for the super user

First data block=0

Maximum filesystem blocks=269484032

64 block groups

16384 blocks per group, 16384 fragments per group

2048 inodes per group

Superblock backups stored on blocks:

        16384, 49152, 81920, 114688, 147456, 409600, 442368, 802816

 

Allocating group tables: done                            

Writing inode tables: done                            

Creating journal (32768 blocks): done

Writing superblocks and filesystem accounting information: done

指定sdb1为2048k块

[[email protected] ~]# mke2fs -b 2048 /dev/sdb1   

mke2fs 1.42.9 (28-Dec-2013)

Filesystem label=

OS type: Linux

Block size=2048 (log=1)

Fragment size=2048 (log=1)

Stride=0 blocks, Stripe width=0 blocks

131072 inodes, 1048576 blocks

52428 blocks (5.00%) reserved for the super user

First data block=0

Maximum filesystem blocks=537919488

64 block groups

16384 blocks per group, 16384 fragments per group

2048 inodes per group

Superblock backups stored on blocks:

        16384, 49152, 81920, 114688, 147456, 409600, 442368, 802816

 

Allocating group tables: done                            

Writing inode tables: done                            

Writing superblocks and filesystem accounting information: done

指定预留给root的磁盘空间

[[email protected] ~]#  mke2fs -t ext4 -m 0.1 /dev/sdb1   #预留百分之1.1的空间给root用户，并指定文件系统格式为ext4，如果不指定则是默认为ext2

mke2fs 1.42.9 (28-Dec-2013)

Filesystem label=

OS type: Linux

Block size=4096 (log=2)

Fragment size=4096 (log=2)

Stride=0 blocks, Stripe width=0 blocks

131072 inodes, 524288 blocks

524 blocks (0.10%) reserved for the super user

First data block=0

Maximum filesystem blocks=536870912

16 block groups

32768 blocks per group, 32768 fragments per group

8192 inodes per group

Superblock backups stored on blocks:

        32768, 98304, 163840, 229376, 294912

 

Allocating group tables: done                            

Writing inode tables: done                            

Creating journal (16384 blocks): done

Writing superblocks and filesystem accounting information: done

mke2fs指定inode对应块大小

[[email protected] ~]# mke2fs -t ext4 -i 8192  /dev/sdb1          #增加inode

mke2fs 1.42.9 (28-Dec-2013)

Filesystem label=

OS type: Linux

Block size=4096 (log=2)

Fragment size=4096 (log=2)

Stride=0 blocks, Stripe width=0 blocks

262144 inodes, 524288 blocks

26214 blocks (5.00%) reserved for the super user

First data block=0

Maximum filesystem blocks=536870912

16 block groups

32768 blocks per group, 32768 fragments per group

16384 inodes per group

Superblock backups stored on blocks:

        32768, 98304, 163840, 229376, 294912

 

Allocating group tables: done                            

Writing inode tables: done                            

Creating journal (16384 blocks): done

Writing superblocks and filesystem accounting information: done

查看分区信息

[[email protected] ~]# blkid /dev/sdb1

/dev/sdb1: UUID="ffd991f6-2fc8-4c56-9ffb-41a9f741d70d" TYPE="ext4"

 

mkfs命令：

支持的文件系统mkfs.btrfs   mkfs.cramfs  mkfs.ext2    mkfs.ext3    mkfs.ext4    mkfs.minix   mkfs.xfs

格式化sdb1为xfs文件系统：

[[email protected] ~]# mkfs.xfs /dev/sdb1 #用mkfs.xfs就可以实现xfs的格式化，如果是已经格式化过的需要加-f强制执行

mkfs.xfs: /dev/sdb1 appears to contain an existing filesystem (ext4).

mkfs.xfs: Use the -f option to force overwrite.

[[email protected] ~]# mkfs.xfs -f /dev/sdb1

meta-data=/dev/sdb1              isize=512    agcount=4, agsize=131072 blks

         =                       sectsz=512   attr=2, projid32bit=1

         =                       crc=1        finobt=0, sparse=0

data     =                       bsize=4096   blocks=524288, imaxpct=25

         =                       sunit=0      swidth=0 blks

naming   =version 2              bsize=4096   ascii-ci=0 ftype=1

log      =internal log           bsize=4096   blocks=2560, version=2

         =                       sectsz=512   sunit=0 blks, lazy-count=1

realtime =none                   extsz=4096   blocks=0, rtextents=0