查看CentOS 7支持的文件系统格式
[root@centos-01 ~]# cat /etc/filesystems xfsext4ext3ext2nodev procnodev devptsiso9660vfathfshfsplus*
mount查看分区的文件系统格式
[root@centos-01 ~]# mountsysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime,seclabel)proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)devtmpfs on /dev type devtmpfs (rw,nosuid,seclabel,size=490008k,nr_inodes=122502,mode=755)securityfs on /sys/kernel/security type securityfs (rw,nosuid,nodev,noexec,relatime)tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev,seclabel)devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,seclabel,gid=5,mode=620,ptmxmode=000)tmpfs on /run type tmpfs (rw,nosuid,nodev,seclabel,mode=755)tmpfs on /sys/fs/cgroup type tmpfs (ro,nosuid,nodev,noexec,seclabel,mode=755)cgroup on /sys/fs/cgroup/systemd type cgroup (rw,nosuid,nodev,noexec,relatime,xattr,release_agent=/usr/lib/systemd/systemd-cgroups-agent,name=systemd)pstore on /sys/fs/pstore type pstore (rw,nosuid,nodev,noexec,relatime)cgroup on /sys/fs/cgroup/hugetlb type cgroup (rw,nosuid,nodev,noexec,relatime,hugetlb)cgroup on /sys/fs/cgroup/pids type cgroup (rw,nosuid,nodev,noexec,relatime,pids)cgroup on /sys/fs/cgroup/perf_event type cgroup (rw,nosuid,nodev,noexec,relatime,perf_event)cgroup on /sys/fs/cgroup/memory type cgroup (rw,nosuid,nodev,noexec,relatime,memory)cgroup on /sys/fs/cgroup/devices type cgroup (rw,nosuid,nodev,noexec,relatime,devices)cgroup on /sys/fs/cgroup/cpu,cpuacct type cgroup (rw,nosuid,nodev,noexec,relatime,cpuacct,cpu)cgroup on /sys/fs/cgroup/net_cls,net_prio type cgroup (rw,nosuid,nodev,noexec,relatime,net_prio,net_cls)cgroup on /sys/fs/cgroup/cpuset type cgroup (rw,nosuid,nodev,noexec,relatime,cpuset)cgroup on /sys/fs/cgroup/freezer type cgroup (rw,nosuid,nodev,noexec,relatime,freezer)cgroup on /sys/fs/cgroup/blkio type cgroup (rw,nosuid,nodev,noexec,relatime,blkio)configfs on /sys/kernel/config type configfs (rw,relatime)/dev/sda3 on / type xfs (rw,relatime,seclabel,attr2,inode64,noquota)selinuxfs on /sys/fs/selinux type selinuxfs (rw,relatime)systemd-1 on /proc/sys/fs/binfmt_misc type autofs (rw,relatime,fd=26,pgrp=1,timeout=0,minproto=5,maxproto=5,direct,pipe_ino=12742)debugfs on /sys/kernel/debug type debugfs (rw,relatime)hugetlbfs on /dev/hugepages type hugetlbfs (rw,relatime,seclabel)mqueue on /dev/mqueue type mqueue (rw,relatime,seclabel)/dev/sda1 on /boot type xfs (rw,relatime,seclabel,attr2,inode64,noquota)tmpfs on /run/user/0 type tmpfs (rw,nosuid,nodev,relatime,seclabel,size=99972k,mode=700)
可以发现，“/”根目录、“/boot”目录都是xfs格式（CentOS 7默认文件系统格式是xfs）。在CentOS 6以及之前的版本，使用的是ext文件系统格式，CentOS 6是ext4格式、CentOS 5是ext3格式。
创建分区
[root@centos-01 ~]# fdisk -l磁盘 /dev/sda：32.2 GB, 32212254720 字节，62914560 个扇区Units = 扇区 of 1 * 512 = 512 bytes扇区大小(逻辑/物理)：512 字节 / 512 字节I/O 大小(最小/最佳)：512 字节 / 512 字节磁盘标签类型：dos磁盘标识符：0x000d9f36 设备 Boot Start End Blocks Id System/dev/sda1 * 2048 411647 204800 83 Linux/dev/sda2 411648 4605951 2097152 82 Linux swap / Solaris/dev/sda3 4605952 62914559 29154304 83 Linux磁盘 /dev/sdb：10.7 GB, 10737418240 字节，20971520 个扇区Units = 扇区 of 1 * 512 = 512 bytes扇区大小(逻辑/物理)：512 字节 / 512 字节I/O 大小(最小/最佳)：512 字节 / 512 字节磁盘标签类型：dos磁盘标识符：0x59b95324 设备 Boot Start End Blocks Id System[root@centos-01 ~]# fdisk /dev/sdb 欢迎使用 fdisk (util-linux 2.23.2)。更改将停留在内存中，直到您决定将更改写入磁盘。使用写入命令前请三思。命令(输入 m 获取帮助)：nPartition type: p primary (0 primary, 0 extended, 4 free) e extendedSelect (default p): p分区号 (1-4，默认 1)：起始 扇区 (2048-20971519，默认为 2048)：将使用默认值 2048Last 扇区, +扇区 or +size{K,M,G} (2048-20971519，默认为 20971519)：+3G分区 1 已设置为 Linux 类型，大小设为 3 GiB命令(输入 m 获取帮助)：wThe partition table has been altered!Calling ioctl() to re-read partition table.正在同步磁盘。[root@centos-01 ~]# fdisk -l磁盘 /dev/sda：32.2 GB, 32212254720 字节，62914560 个扇区Units = 扇区 of 1 * 512 = 512 bytes扇区大小(逻辑/物理)：512 字节 / 512 字节I/O 大小(最小/最佳)：512 字节 / 512 字节磁盘标签类型：dos磁盘标识符：0x000d9f36 设备 Boot Start End Blocks Id System/dev/sda1 * 2048 411647 204800 83 Linux/dev/sda2 411648 4605951 2097152 82 Linux swap / Solaris/dev/sda3 4605952 62914559 29154304 83 Linux磁盘 /dev/sdb：10.7 GB, 10737418240 字节，20971520 个扇区Units = 扇区 of 1 * 512 = 512 bytes扇区大小(逻辑/物理)：512 字节 / 512 字节I/O 大小(最小/最佳)：512 字节 / 512 字节磁盘标签类型：dos磁盘标识符：0x59b95324 设备 Boot Start End Blocks Id System/dev/sdb1 2048 6293503 3145728 83 Linux 格式化
mkfs.ext4等价于mke2fs -t ext4
[root@centos-01 ~]# mke2fs -t ext4 /dev/sdb1 mke2fs 1.42.9 (28-Dec-2013)文件系统标签=OS type: Linux块大小=4096 (log=2)分块大小=4096 (log=2)Stride=0 blocks, Stripe width=0 blocks196608 inodes, 786432 blocks39321 blocks (5.00%) reserved for the super user第一个数据块=0Maximum filesystem blocks=80530636824 block groups32768 blocks per group, 32768 fragments per group8192 inodes per groupSuperblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912Allocating group tables: 完成 正在写入inode表: 完成 Creating journal (16384 blocks): 完成Writing superblocks and filesystem accounting information: 完成
这里换种方式再次格式化。分区即使格式化过一次，还可以再次格式化。
[root@centos-01 ~]# mkfs.ext4 /dev/sdb1 mke2fs 1.42.9 (28-Dec-2013)文件系统标签=OS type: Linux块大小=4096 (log=2)分块大小=4096 (log=2)Stride=0 blocks, Stripe width=0 blocks196608 inodes, 786432 blocks39321 blocks (5.00%) reserved for the super user第一个数据块=0Maximum filesystem blocks=80530636824 block groups32768 blocks per group, 32768 fragments per group8192 inodes per groupSuperblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912Allocating group tables: 完成 正在写入inode表: 完成 Creating journal (16384 blocks): 完成Writing superblocks and filesystem accounting information: 完成
- mke2fs无法格式化成xfs格式
[root@centos-01 ~]# mke2fs -t xfs /dev/sdb1 mke2fs 1.42.9 (28-Dec-2013)Your mke2fs.conf file does not define the xfs filesystem type.Aborting...
- 用
mkfs.xfs可以格式化成xfs格式，不过因为分区之前已经格式化过，需要用‘-f’选项再次格式化。
[root@centos-01 ~]# mkfs.xfs /dev/sdb1 mkfs.xfs: /dev/sdb1 appears to contain an existing filesystem (ext4).mkfs.xfs: Use the -f option to force overwrite.[root@centos-01 ~]# mkfs.xfs -f /dev/sdb1 meta-data=/dev/sdb1 isize=512 agcount=4, agsize=196608 blks = sectsz=512 attr=2, projid32bit=1 = crc=1 finobt=0, sparse=0data = bsize=4096 blocks=786432, imaxpct=25 = sunit=0 swidth=0 blksnaming =version 2 bsize=4096 ascii-ci=0 ftype=1log =internal log bsize=4096 blocks=2560, version=2 = sectsz=512 sunit=0 blks, lazy-count=1realtime =none extsz=4096 blocks=0, rtextents=0
- 查看还没有挂载分区的格式（/dev/sdb1还未挂载）
[root@centos-01 ~]# blkid /dev/sdb1 /dev/sdb1: UUID="b6615809-31bf-4a30-8a9c-6550bd8f9d1f" TYPE="xfs"
mke2fs命令
- ‘-t’：指定文件系统类型
- ‘-b’：指定区块大小，单位为字节
[root@centos-01 ~]# mke2fs -b 8192 /dev/sdb1 Warning: blocksize 8192 not usable on most systems.mke2fs 1.42.9 (28-Dec-2013)mke2fs: 8192-byte blocks too big for system (max 4096)无论如何也要继续? (y,n) n[root@centos-01 ~]# mke2fs -b 2048 /dev/sdb1 mke2fs 1.42.9 (28-Dec-2013)文件系统标签=OS type: Linux块大小=2048 (log=1)分块大小=2048 (log=1)Stride=0 blocks, Stripe width=0 blocks196608 inodes, 1572864 blocks78643 blocks (5.00%) reserved for the super user第一个数据块=0Maximum filesystem blocks=53896806496 block groups16384 blocks per group, 16384 fragments per group2048 inodes per groupSuperblock backups stored on blocks: 16384, 49152, 81920, 114688, 147456, 409600, 442368, 802816, 1327104Allocating group tables: 完成 正在写入inode表: 完成 Writing superblocks and filesystem accounting information: 完成
- ‘-m’：指定分区预留大小。预设为5%。
[root@centos-01 ~]# mke2fs -m 1 /dev/sdb1 mke2fs 1.42.9 (28-Dec-2013)文件系统标签=OS type: Linux块大小=4096 (log=2)分块大小=4096 (log=2)Stride=0 blocks, Stripe width=0 blocks196608 inodes, 786432 blocks7864 blocks (1.00%) reserved for the super user第一个数据块=0Maximum filesystem blocks=80530636824 block groups32768 blocks per group, 32768 fragments per group8192 inodes per groupSuperblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912Allocating group tables: 完成 正在写入inode表: 完成 Writing superblocks and filesystem accounting information: 完成 [root@centos-01 ~]# mke2fs -m 0.1 /dev/sdb1 mke2fs 1.42.9 (28-Dec-2013)文件系统标签=OS type: Linux块大小=4096 (log=2)分块大小=4096 (log=2)Stride=0 blocks, Stripe width=0 blocks196608 inodes, 786432 blocks786 blocks (0.10%) reserved for the super user第一个数据块=0Maximum filesystem blocks=80530636824 block groups32768 blocks per group, 32768 fragments per group8192 inodes per groupSuperblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912Allocating group tables: 完成 正在写入inode表: 完成 Writing superblocks and filesystem accounting information: 完成
- 前面的命令没有指定文件系统类型，用
blkid命令查看前面命令执行后格式化的类型。
[root@centos-01 ~]# blkid /dev/sdb1 /dev/sdb1: UUID="2b56d897-2b84-4628-aafa-319e1812210c" TYPE="ext2"
如果不指定文件系统类型，就是ext2格式。
[root@centos-01 ~]# mke2fs -t ext4 -m 0.1 /dev/sdb1 mke2fs 1.42.9 (28-Dec-2013)文件系统标签=OS type: Linux块大小=4096 (log=2)分块大小=4096 (log=2)Stride=0 blocks, Stripe width=0 blocks196608 inodes, 786432 blocks786 blocks (0.10%) reserved for the super user第一个数据块=0Maximum filesystem blocks=80530636824 block groups32768 blocks per group, 32768 fragments per group8192 inodes per groupSuperblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912Allocating group tables: 完成 正在写入inode表: 完成 Creating journal (16384 blocks): 完成Writing superblocks and filesystem accounting information: 完成 [root@centos-01 ~]# mkfs.ext4 -m 0.1 /dev/sdb1 mke2fs 1.42.9 (28-Dec-2013)文件系统标签=OS type: Linux块大小=4096 (log=2)分块大小=4096 (log=2)Stride=0 blocks, Stripe width=0 blocks196608 inodes, 786432 blocks786 blocks (0.10%) reserved for the super user第一个数据块=0Maximum filesystem blocks=80530636824 block groups32768 blocks per group, 32768 fragments per group8192 inodes per groupSuperblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912Allocating group tables: 完成 正在写入inode表: 完成 Creating journal (16384 blocks): 完成Writing superblocks and filesystem accounting information: 完成
- ‘-i<字节>’：指定”字节/inode”的比例。默认是4个块（block）对应一个inode，也就是4*4K=16K=16384Byte / 1 inode。
[root@centos-01 ~]# mke2fs -i 8192 -t ext4 /dev/sdb1 mke2fs 1.42.9 (28-Dec-2013)文件系统标签=OS type: Linux块大小=4096 (log=2)分块大小=4096 (log=2)Stride=0 blocks, Stripe width=0 blocks393216 inodes, 786432 blocks39321 blocks (5.00%) reserved for the super user第一个数据块=0Maximum filesystem blocks=80530636824 block groups32768 blocks per group, 32768 fragments per group16384 inodes per groupSuperblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912Allocating group tables: 完成 正在写入inode表: 完成 Creating journal (16384 blocks): 完成Writing superblocks and filesystem accounting information: 完成