Unit13

磁盘管理（上）

1、磁盘的扇区 磁盘的第一个扇区主要记录了两个重要的信息： 主引导分区（MBR）：可以安装引导加载程序的地方，有446bytes 分区表：记录整块硬盘分区的状态，有64bytes 硬盘有效性标示 主分区 扩展分区 逻辑分区 MBR是很重要的，因为当系统在开机的时候会主动去读取这个区块的内容

fdisk -l ##系统中的所有磁盘设备 df -TH ##系统正在挂载的磁盘设备 blkid ##系统可以挂载的磁盘设备id

2、分区划分 fidsk /dev/vdb

[root@localhost ~]# fdisk /dev/vdb 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): m ##获得帮助 Command action a toggle a bootable flag b edit bsd disklabel c toggle the dos compatibility flag d delete a partition ##删除分区 g create a new empty GPT partition table G create an IRIX (SGI) partition table l list known partition types ##列出系统可用分区类型 m print this menu n add a new partition ##新建分区 o create a new empty DOS partition table p print the partition table ##显示分区 q quit without saving changes ##退出 s create a new empty Sun disklabel t change a partition's system id ##修改分区功能id u change display/entry units v verify the partition table w write table to disk and exit ##保存更改到分区表中 x extra functionality (experts only) Command (m for help): n ##新建分区 Partition type: p primary (1 primary, 0 extended, 3 free) ##分区类型为主分区 e extended ##分区类型为扩展分区 Select (default p): p Partition number (2-4, default 2): 2 ##主分区id First sector (206848-20971519, default 206848): ##此分区的起始位置 Using default value 206848 Last sector, +sectors or +size{K,M,G} (206848-20971519, default 20971519): +200M ##分区大小 Partition 2 of type Linux and of size 200 MiB is set Command (m for help): wq ##**保存并退出，只输入q则表示放弃更改退出** The partition table has been altered! partprobe ##同步分区表 mkfs.xfs /dev/vdb1 ##格式化 mount /dev/vdb1 /mnt ##临时挂载 vim /etc/fstab ##永久挂载 编写格式： device mountpoint ftype defaults(mountpoint) 0 0 /dev/vdb1 /mnt xfs defaults 0 0 mount -a ##使/etc/fastab中记录的挂载生效

分区删除 先使用umount命令解除挂载 PS：当挂载点被使用时，无法解除挂载，需要用fuser -kvm结束使用的进程，然后进行解除挂载 解除挂载之后，使用fdisk /dev/vdb命令 删除分区

5.设定分区方式,将mkdocs 改为 gpt 更改之前需要把正在使用的分区关闭，才可以进行更改 partoff /dev/vdb2 parted /dev/vdb

添加swap分区 使用磁盘分区

[root@localhost ~]# fdisk /dev/vdb WARNING: fdisk GPT support is currently new, and therefore in an experimental phase. Use at your own discretion. 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 Partition number (2-128, default 2): First sector (34-20971486, default 2099200): Last sector, +sectors or +size{K,M,G,T,P} (2099200-20971486, default 20971486): +4G Created partition 2 Command (m for help): p Disk /dev/vdb: 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: gpt tart End Size Type Name 1 2048 2099199 1G Linux filesyste 2 2099200 10487807 4G Linux filesyste Command (m for help): t Partition number (1,2, default 2): 2 Partition type (type L to list all types): l **14 Linux swap 0657FD6D-A4AB-43C4-84E5-0933C84B4F4F** Partition type (type L to list all types): 14 Changed type of partition 'Linux filesystem' to 'Linux swap' Command (m for help): p Disk /dev/vdb: 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: gpt Start End Size Type Name 1 2048 2099199 1G Linux filesyste 2 2099200 10487807 4G Linux swap Command (m for help): wq 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@localhost ~]# [root@localhost ~]# partprobe ##同步分区表 [root@localhost ~]# mkswap /dev/vdb2 ##格式化成swap类型 Setting up swapspace version 1, size = 4194300 KiB no label, UUID=b933737a-1409-48b5-8f92-d663d388134b [root@localhost ~]# swapon -a /dev/vdb2 ##加入swap [root@localhost ~]# swapon -s Filename Type Size Used Priority /dev/vdb2 partition 4194300 0 -1 [root@localhost ~]#

使用文件添加swap

dd if=/dev/zero of=/swapfile bs=1M count=1000 ##创建一个1G大小的文件 mkswap /swapfile ##格式化为swap类型 swapon -a /swapfile ##临时添加到swap里 -p + 数字 ##更改优先级 vim /etc/fstab ##永久添加swap分区

类型： /swapfile swap swap defaults,pri=1 0 0 #pri优先级

删除swap

vim /etc/fstab ##删除此文件中添加的swap行 swapoff /swapfile ##断开swap文件链接 swapoff /dev/vdb1 ##断开swap磁盘链接 rm -rf /swapfile ##删除文件 fdisk /dev/vdb ##删除磁盘分区 partprobe ##同步分区表