磁盘的相关知识
1、磁盘的命名
2、硬盘的分区方式
MBR 分区方式（小于2T），使用fdisk命令：4个主分区或者3个主分区+一个扩展分区（N各逻辑分区）
GPT分区方案（大于2T），使用gdisk（parted）：128个主分区
3、fdisk分区磁盘
首先查看磁盘的分区情况 lsblk
[root@localhost ~]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 20G 0 disk ├─sda1 8:1 0 1G 0 part /boot └─sda2 8:2 0 19G 0 part ├─centos-root 253:0 0 17G 0 lvm / └─centos-swap 253:1 0 2G 0 lvm [SWAP] sdb 8:16 0 2G 0 disk sr0 11:0 1 4.4G 0 rom
查看正在挂载的设备情况
[root@localhost ~]# df -h Filesystem Size Used Avail Use% Mounted on devtmpfs 898M 0 898M 0% /dev tmpfs 910M 0 910M 0% /dev/shm tmpfs 910M 9.5M 901M 2% /run tmpfs 910M 0 910M 0% /sys/fs/cgroup /dev/mapper/centos-root 17G 1.4G 16G 9% / /dev/sda1 1014M 150M 865M 15% /boot tmpfs 182M 0 182M 0% /run/user/0
开始分区
[root@localhost ~]# fdisk /dev/sdb Command (m for help): n Partition type: p primary (0 primary, 0 extended, 4 free) e extended Select (default p): p Partition number (1-4, default 1): 1 First sector (2048-4194303, default 2048): Using default value 2048 Last sector, +sectors or +size{K,M,G} (2048-4194303, default 4194303): +1G Partition 1 of type Linux and of size 1 GiB is set Command (m for help): p Disk /dev/sdb: 2147 MB, 2147483648 bytes, 4194304 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: 0xfd063994 Device Boot Start End Blocks Id System /dev/sdb1 2048 2099199 1048576 83 Linux Command (m for help): n Partition type: p primary (1 primary, 0 extended, 3 free) e extended Select (default p): p Partition number (2-4, default 2): 2 First sector (2099200-4194303, default 2099200): Using default value 2099200 Last sector, +sectors or +size{K,M,G} (2099200-4194303, default 4194303): +500M Partition 2 of type Linux and of size 500 MiB is set Command (m for help): p Disk /dev/sdb: 2147 MB, 2147483648 bytes, 4194304 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: 0xfd063994 Device Boot Start End Blocks Id System /dev/sdb1 2048 2099199 1048576 83 Linux /dev/sdb2 2099200 3123199 512000 83 Linux Command (m for help): w The partition table has been altered! Calling ioctl() to re-read partition table. Syncing disks.
分区后查看，其中sdb3是扩展分区，
[root@localhost ~]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 20G 0 disk ├─sda1 8:1 0 1G 0 part /boot └─sda2 8:2 0 19G 0 part ├─centos-root 253:0 0 17G 0 lvm / └─centos-swap 253:1 0 2G 0 lvm [SWAP] sdb 8:16 0 2G 0 disk ├─sdb1 8:17 0 1G 0 part ├─sdb2 8:18 0 500M 0 part ├─sdb3 8:19 0 1K 0 part └─sdb5 8:21 0 522M 0 part sr0 11:0 1 4.4G 0 rom
刷新分区表
[root@localhost ~]# partx -a /dev/sdb partx: /dev/sdb: error adding partitions 1-3 partx: /dev/sdb: error adding partition 5
格式化
[root@localhost ~]# mkfs.ext4 /dev/sdb1 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 65536 inodes, 262144 blocks 13107 blocks (5.00%) reserved for the super user First data block=0 Maximum filesystem blocks=268435456 8 block groups 32768 blocks per group, 32768 fragments per group 8192 inodes per group Superblock backups stored on blocks: 32768, 98304, 163840, 229376 Allocating group tables: done Writing inode tables: done Creating journal (8192 blocks): done Writing superblocks and filesystem accounting information: done
挂载：
[root@localhost ~]# mount /dev/sdb1 u01 [root@localhost ~]# df -h Filesystem Size Used Avail Use% Mounted on devtmpfs 898M 0 898M 0% /dev tmpfs 910M 0 910M 0% /dev/shm tmpfs 910M 9.6M 901M 2% /run tmpfs 910M 0 910M 0% /sys/fs/cgroup /dev/mapper/centos-root 17G 1.4G 16G 9% / /dev/sda1 1014M 150M 865M 15% /boot tmpfs 182M 0 182M 0% /run/user/0 /dev/sdb1 976M 2.6M 907M 1% /root/u01
重新挂载一个已经挂载的设备
[root@localhost ~]# mount -o remount,ro /dev/sdb1
也可以使用UUID挂载
[root@localhost ~]# blkid /dev/sdb5 /dev/sdb5: UUID="35ead5d1-7cb8-41de-89e1-f4676fa324d1" TYPE="ext4" [root@localhost ~]# mount UUID="35ead5d1-7cb8-41de-89e1-f4676fa324d1" u05
4、主分区、扩展分区、逻辑分区
一块硬盘可以不要主分区，可以直接分为扩展分区和逻辑分区
- 主分区是硬盘的启动分区,他是独立的,也是硬盘的第一个分区。
- 分出主分区后,其余的部分可以分成扩展分区,一般是剩下的部分全部分成扩展分区,也可以不全分,那剩的部分就浪费了。
- 但扩展分区是不能直接用的,他是以逻辑分区的方式来使用的,所以说扩展分区可分成若干逻辑分区。他们的关系是包含的关系,所有的逻辑分区都是扩展分区的一部分
5、逻辑卷管理
创建PV
[root@localhost ~]# pvcreate /dev/sdc1 Physical volume "/dev/sdc1" successfully created. [root@localhost ~]# pvcreate /dev/sdc2 Physical volume "/dev/sdc2" successfully created.
创建VG
[root@localhost ~]# vgcreate vg01 /dev/sdc1 /dev/sdc2 Volume group "vg01" successfully created
创建LV
[root@localhost ~]# lvcreate -n lv01 -L 1.9G vg01 Rounding up size to full physical extent 1.90 GiB Logical volume "lv01" created.
格式化
[root@localhost ~]# mkfs.ext4 /dev/vg01/lv01 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 124672 inodes, 498688 blocks 24934 blocks (5.00%) reserved for the super user First data block=0 Maximum filesystem blocks=511705088 16 block groups 32768 blocks per group, 32768 fragments per group 7792 inodes per group Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912 Allocating group tables: done Writing inode tables: done Creating journal (8192 blocks): done Writing superblocks and filesystem accounting information: done
挂载
[root@localhost ~]# mount /dev/vg01/lv01 u06
6、软连接
创建软连接
ln -s 目标文件 连接文件
[root@localhost ~]# touch file1
[root@localhost ~]# ln -s file1 test1
查看链接文件
[root@localhost ~]# ll lrwxrwxrwx. 1 root root 5 Jun 16 04:24 test1 -> file1
修改原文件，连接文件会变，修改连接文件，原文件也会变
[root@localhost ~]# echo hello >> file1 [root@localhost ~]# cat test1 hello [root@localhost ~]# echo world >> test1
原文件和链接文件是两个不同的文件
[root@localhost ~]# ll -i 33940254 -rw-r--r--. 1 root root 12 Jun 16 04:25 file1 33940255 lrwxrwxrwx. 1 root root 5 Jun 16 04:24 test1 -> file1
删除原文件，链接文件变为无效文件
[root@localhost ~]# rm file1
rm: remove regular file ‘file1’? y
删除目录的软链接，一定要注意软链接的目录后边不能加斜杠，如果加了会删除目录里边的内容
[root@localhost link]# rm -rf test2
也可以用unlink命令后面跟软链接的名称
[root@localhost link]# unlink testlink1
7、硬连接
硬链接特点：
- 文件内容相同；
- 一个文件改变另一个文件也改变；
- 删除一个文件不会影响其他文件；
- inode号相同
- Linux中，不能对目录创建硬链接。
创建硬连接
[root@localhost link]# touch file1 [root@localhost link]# ln file1 test1 [root@localhost link]# ll -i total 0 16785871 -rw-r--r--. 2 root root 0 Jun 16 05:04 file1 16785871 -rw-r--r--. 2 root root 0 Jun 16 05:04 te
