【CentOS 7笔记21】，磁盘挂载#

shallow丿ove

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不进行分区直接格式化

[root@localhost ~]# fdisk -l /dev/sdb

	Disk /dev/sdb: 10.7 GB, 10737418240 bytes, 20971520 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: 0xa8f0c23e

	   Device Boot      Start         End      Blocks   Id  System

[root@localhost ~]# mkfs.xfs /dev/sdb
	mkfs.xfs: /dev/sdb appears to contain a partition table (dos).
	mkfs.xfs: Use the -f option to force overwrite.
[root@localhost ~]# mkfs.xfs -f /dev/sdb
	meta-data=/dev/sdb               isize=256    agcount=4, agsize=655360 blks
	         =                       sectsz=512   attr=2, projid32bit=1
	         =                       crc=0
	data     =                       bsize=4096   blocks=2621440, imaxpct=25
	         =                       sunit=0      swidth=0 blks
	naming   =version 2              bsize=4096   ascii-ci=0 ftype=0
	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

[root@localhost ~]# blkid /dev/sdb
	/dev/sdb: UUID="ad9ebef7-36c8-4395-a697-ffd8ae481541" TYPE="xfs"

格式化分区的目的是为了挂载文件系统，Linux要想访问磁盘必须挂载挂载点，挂载点其实就是一个目录

mount挂载

[root@localhost ~]# mount /dev/sdb /mnt/
[root@localhost ~]# df -h
	Filesystem      Size  Used Avail Use% Mounted on
	/dev/sda3        28G  848M   27G   3% /
	devtmpfs        909M     0  909M   0% /dev
	tmpfs           914M     0  914M   0% /dev/shm
	tmpfs           914M  8.5M  905M   1% /run
	tmpfs           914M     0  914M   0% /sys/fs/cgroup
	/dev/sda1       197M   75M  123M  38% /boot
	/dev/sdb         10G   33M   10G   1% /mnt
[root@localhost ~]# mount | grep /dev/sd
	/dev/sda3 on / type xfs (rw,relatime,seclabel,attr2,inode64,noquota)
	/dev/sda1 on /boot type xfs (rw,relatime,seclabel,attr2,inode64,noquota)
	/dev/sdb on /mnt type xfs (rw,relatime,seclabel,attr2,inode64,noquota)

umount卸载

[root@localhost ~]# cd /mnt/
[root@localhost mnt]# ls
[root@localhost mnt]# ls
[root@localhost mnt]# touch 1.txt 2.txt
[root@localhost mnt]# mkdir 111
[root@localhost mnt]# ls
	111  1.txt  2.txt
[root@localhost mnt]# umount /dev/sdb
	umount: /mnt: target is busy.
	        (In some cases useful info about processes that use
	         the device is found by lsof(8) or fuser(1))
[root@localhost mnt]# pwd
	/mnt

当前在/mnt/目录中，必须退出当前目录才能够继续umount

[root@localhost mnt]# cd
[root@localhost ~]# umount /dev/sdb
[root@localhost ~]# df -h
	Filesystem      Size  Used Avail Use% Mounted on
	/dev/sda3        28G  846M   27G   3% /
	devtmpfs        909M     0  909M   0% /dev
	tmpfs           914M     0  914M   0% /dev/shm
	tmpfs           914M  8.5M  905M   1% /run
	tmpfs           914M     0  914M   0% /sys/fs/cgroup
	/dev/sda1       197M   75M  123M  38% /boot

当继续挂载目录，

[root@localhost ~]# mount /dev/sdb /mnt/
[root@localhost ~]# cd /mnt
[root@localhost mnt]# ls
	111  1.txt  2.txt

umount -l能够不用退出当前目录，即可以直接umount

[root@localhost mnt]# umount /dev/sdb
	umount: /mnt: target is busy.
	        (In some cases useful info about processes that use
	         the device is found by lsof(8) or fuser(1))
[root@localhost mnt]# umount -l /dev/sdb
[root@localhost mnt]# df -h
	Filesystem      Size  Used Avail Use% Mounted on
	/dev/sda3        28G  846M   27G   3% /
	devtmpfs        909M     0  909M   0% /dev
	tmpfs           914M     0  914M   0% /dev/shm
	tmpfs           914M  8.5M  905M   1% /run
	tmpfs           914M     0  914M   0% /sys/fs/cgroup
	/dev/sda1       197M   75M  123M  38% /boot

经常使用

mount -o rw\ro
mount -o remount	#从新挂载

系统启动默认挂载的磁盘

[root@localhost mnt]# vi /etc/fstab
	
	#
	# /etc/fstab
	# Created by anaconda on Tue Oct 17 21:12:03 2017
	#
	# Accessible filesystems, by reference, are maintained under '/dev/disk'
	# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
	#
	UUID=915e2a85-8d48-4667-9001-eae59adccb98 /                       xfs     defaults        1 1
	UUID=f50883db-5558-4813-8053-67e97169c609 /boot                   xfs     defaults        1 2
	UUID=d0344494-65f1-4279-a595-76801470be33 swap                    swap    defaults        0 0

系统启动默认挂载哪一个磁盘哪一个分区 第一列设备的设备号，第二列为挂载点，第三列为分区格式，第四列为挂载选项，第五列为是否备份，第六列为优先级1 这里能够写分区号，也能够写UUID，而UUID能够经过blkid查看

[root@localhost mnt]# blkid
	/dev/sr0: UUID="2017-10-27-14-49-48-00" LABEL="20171027_144209" TYPE="iso9660" 
	/dev/sda1: UUID="f50883db-5558-4813-8053-67e97169c609" TYPE="xfs" 
	/dev/sda2: UUID="d0344494-65f1-4279-a595-76801470be33" TYPE="swap" 
	/dev/sda3: UUID="915e2a85-8d48-4667-9001-eae59adccb98" TYPE="xfs" 
	/dev/sdb: UUID="ad9ebef7-36c8-4395-a697-ffd8ae481541" TYPE="xfs" 
[root@localhost mnt]# mount UUID="ad9ebef7-36c8-4395-a697-ffd8ae481541" /mnt/
[root@localhost mnt]# df -h
	Filesystem      Size  Used Avail Use% Mounted on
	/dev/sda3        28G  846M   27G   3% /
	devtmpfs        909M     0  909M   0% /dev
	tmpfs           914M     0  914M   0% /dev/shm
	tmpfs           914M  8.5M  905M   1% /run
	tmpfs           914M     0  914M   0% /sys/fs/cgroup
	/dev/sda1       197M   75M  123M  38% /boot
	/dev/sdb         10G   33M   10G   1% /mnt