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  • Linux-磁盘管理小结

    这篇博文主要总结了Linux磁盘的一些操作,主要是硬盘的加载,分区(MBR分区和GPT分区),分区的挂载,以及swap分区的加载设置。


    基础命令

    • df查看磁盘分区使用状况
      1. -l //仅显示本地磁盘(默认)
      2. -a //显示所有文件系统的磁盘使用情况,包含比如/proc/
      3. -h //以1024进制计算最合适的单位显示磁盘容量
      4. -H //以1000进制计算最合适的单位显示磁盘容量
      5. -t //显示指定类型文件系统的磁盘分区
      6. -T //显示磁盘分区类型
      7. -x //不显示指定类型文件系统的磁盘分区
    • du统计磁盘上的文件大小
      1. -b //以byte为单位统计文件
      2. -k //以KB为单位统计文件
      3. -m //以MB为单位统计文件
      4. -h //以1024进制计算最合适的单位显示磁盘容量
      5. -H //以1000进制计算最合适的单位显示磁盘容量
      6. -s //统计指定目标
    • 常用命令
      1. df -lhT
      2. df -lhT -t ext4(分区类型)
      3. df -lhT -x ext4
      4. du -s [指定目录]
      5. du -sb *.zip //模糊匹配
      6. du -sm *.zip
      7. du -sh *.zip

    回顾磁盘分区时的注意事项:

    • 主分区和扩展分区总数不能超过4个。
    • 扩展分区最多只能有一个
    • 扩展分区不能直接存取数据
      小知识:
    • Linux系统中硬件设备都是以文件的形式存在于根目录下的Dev目录下。
    • 硬件设备都是有Linux系统自动识别的。
    • 添加的新硬盘,必须进行分区、格式化、挂载后才能使用。
    • MBR分区模式:主分区不超过4个,单个分区容量最大为2TB
    • GPT分区模式:主分区个数“几乎”没有限制,单个分区容量“几乎”没有限制。GPT分区中,最多可以支持128个主分区,且每个分区的大小突破了MBR分区的2TB的限制,最大为18EB=18432PB=18874368TB。缺点是GPT的主分区中,不适合安装X86架构的系统。

    当硬盘空间消耗殆尽时怎么办?

    比较好的做法应该是:在保留原硬盘的基础上,给服务器添加新的硬盘。


    为虚拟机添加硬盘

    1. 将虚拟机关机(poweroff)。(当然,也有服务器的主板支持热插拔的。可以带电连接新硬盘。)
    2. 虚拟机设置->下面的“添加”->类型选择“硬盘”->下一步->选择硬盘类型(默认的(SCSI)就好)->创建一个新的虚拟机硬盘(下一步)->设置磁盘最大值;(没什么特殊要求,基本都是下一步,最后一步OK)。
    3. 重启Linux系统,使用fdisk -l//显示每个硬盘的分区列表(新添加的硬盘是没有分区表的)可以看到Disk /dev/sdb:和Disk /dev/sda:2块硬盘,以及sda的分区表,没有sdb的分区表。
    4. 先使用MBR分区模式为sdb分区。
      [root@joe dev]# 
      fdisk /dev/sdb
          //进入分区模式
      Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
      Building a new DOS disklabel with disk identifier 0x9ce83f46.
      Changes will remain in memory only, until you decide to write them.
      After that, of course, the previous content won't be recoverable.
      
      Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
      
      WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
               switch off the mode (command 'c') and change display units to
               sectors (command 'u').
      
      Command (m for help):
      m
         //查看帮助
      Command action
         a   toggle a bootable flag
         b   edit bsd disklabel
         c   toggle the dos compatibility flag
         d   delete a partition    //删除一个分区
         l   list known partition types
         m   print this menu
         n   add a new partition    //添加新的分区
         o   create a new empty DOS partition table
         p   print the partition table    //打印分区表
         q   quit without saving changes    //取消保存并退出
         s   create a new empty Sun disklabel
         t   change a partition's system id    //修改分区的系统ID
         u   change display/entry units
         v   verify the partition table
         w   write table to disk and exit        //写分区表并退出
         x   extra functionality (experts only)
      
      Command (m for help): n
      Command action
         e   extended        //扩展分区
         p   primary partition (1-4)//主分区
      p
      Partition number (1-4):
      1
      
      First cylinder (1-2610, default 1):         //扇区的范围(1-2610),默认开始1,直接回车则使用默认数值
      Using default value 1
      Last cylinder, +cylinders or +size{K,M,G} (1-2610, default 2610): 500M
      
      Command (m for help): p
      
      Disk /dev/sdb: 21.5 GB, 21474836480 bytes
      255 heads, 63 sectors/track, 2610 cylinders
      Units = cylinders of 16065 * 512 = 8225280 bytes
      Sector size (logical/physical): 512 bytes / 512 bytes
      I/O size (minimum/optimal): 512 bytes / 512 bytes
      Disk identifier: 0x9ce83f46
      
         Device Boot      Start         End      Blocks   Id  System
      /dev/sdb1               1         500     4016218+  83  Linux        //分配好的主分区1
      //添加第二个分区
      Command (m for help): n
      Command action
         e   extended
         p   primary partition (1-4)
      p
      Partition number (1-4): 
      Value out of range.
      Partition number (1-4): 2
      First cylinder (501-2610, default 501): 
      Using default value 501
      Last cylinder, +cylinders or +size{K,M,G} (501-2610, default 2610): 500M
      Value out of range.
      Last cylinder, +cylinders or +size{K,M,G} (501-2610, default 2610): 
      Using default value 2610
      
      Command (m for help): p
      
      Disk /dev/sdb: 21.5 GB, 21474836480 bytes
      255 heads, 63 sectors/track, 2610 cylinders
      Units = cylinders of 16065 * 512 = 8225280 bytes
      Sector size (logical/physical): 512 bytes / 512 bytes
      I/O size (minimum/optimal): 512 bytes / 512 bytes
      Disk identifier: 0x9ce83f46
      
         Device Boot      Start         End      Blocks   Id  System
      /dev/sdb1               1         500     4016218+  83  Linux
      /dev/sdb2             501        2610    16948575   83  Linux        //第二个分区
      //由于分配不合适主观意愿,想删除分区
      Command (m for help): d
      Partition number (1-4):
      2
            //分区编号
      
      Command (m for help): p
      
      Disk /dev/sdb: 21.5 GB, 21474836480 bytes
      255 heads, 63 sectors/track, 2610 cylinders
      Units = cylinders of 16065 * 512 = 8225280 bytes
      Sector size (logical/physical): 512 bytes / 512 bytes
      I/O size (minimum/optimal): 512 bytes / 512 bytes
      Disk identifier: 0x9ce83f46
      
         Device Boot      Start         End      Blocks   Id  System
      /dev/sdb1               1         500     4016218+  83  Linux        //第二个分区已经删除
      
      Command (m for help): n
      Command action
         e   extended
         p   primary partition (1-4)
      p
      Partition number (1-4):
      2
      
      First cylinder (501-2610, default 501): 
      Using default value 501
      Last cylinder, +cylinders or +size{K,M,G} (501-2610, default 2610): 1000
      
      Command (m for help): p
      
      Disk /dev/sdb: 21.5 GB, 21474836480 bytes
      255 heads, 63 sectors/track, 2610 cylinders
      Units = cylinders of 16065 * 512 = 8225280 bytes
      Sector size (logical/physical): 512 bytes / 512 bytes
      I/O size (minimum/optimal): 512 bytes / 512 bytes
      Disk identifier: 0x9ce83f46
      
         Device Boot      Start         End      Blocks   Id  System
      /dev/sdb1               1         500     4016218+  83  Linux
      /dev/sdb2             501        1000     4016250   83  Linux
      
      Command (m for help): n
      Command action
         e   extended
         p   primary partition (1-4)
      e    //建立扩展分区
      Partition number (1-4):
      3
      
      First cylinder (1001-2610, default 1001): 
      Using default value 1001
      Last cylinder, +cylinders or +size{K,M,G} (1001-2610, default 2610): 
      Using default value 2610
      
      Command (m for help): p
      
      Disk /dev/sdb: 21.5 GB, 21474836480 bytes
      255 heads, 63 sectors/track, 2610 cylinders
      Units = cylinders of 16065 * 512 = 8225280 bytes
      Sector size (logical/physical): 512 bytes / 512 bytes
      I/O size (minimum/optimal): 512 bytes / 512 bytes
      Disk identifier: 0x9ce83f46
      
         Device Boot      Start         End      Blocks   Id  System
      /dev/sdb1               1         500     4016218+  83  Linux
      /dev/sdb2             501        1000     4016250   83  Linux
      /dev/sdb3            1001        2610    12932325    5  Extended
      
      Command (m for help): n
      Command action
         l   logical (
      5 or over)
          //此时扩展分区e没有了,说明MBR只能有一个扩展分区,接下来是逻辑分区
         p   primary partition (1-4)
      l
      First cylinder (1001-2610, default 1001): 
      Using default value 1001
      Last cylinder, +cylinders or +size{K,M,G} (1001-2610, default 2610): 1500
      
      Command (m for help): p
      
      Disk /dev/sdb: 21.5 GB, 21474836480 bytes
      255 heads, 63 sectors/track, 2610 cylinders
      Units = cylinders of 16065 * 512 = 8225280 bytes
      Sector size (logical/physical): 512 bytes / 512 bytes
      I/O size (minimum/optimal): 512 bytes / 512 bytes
      Disk identifier: 0x9ce83f46
      
         Device Boot      Start         End      Blocks   Id  System
      /dev/sdb1               1         500     4016218+  83  Linux
      /dev/sdb2             501        1000     4016250   83  Linux
      /dev/sdb3            1001        2610    12932325    5  Extended
      /dev/sdb5            1001        1500     4016218+  83  Linux        //逻辑分区是从5开始的,1-4只能是主分区和扩展分区的编号
      
      Command (m for help): n
      Command action
         l   logical (5 or over)
         p   primary partition (1-4)
      l
      First cylinder (1501-2610, default 1501): 
      Using default value 1501
      Last cylinder, +cylinders or +size{K,M,G} (1501-2610, default 2610): 
      Using default value 2610
      
      Command (m for help): p
      
      Disk /dev/sdb: 21.5 GB, 21474836480 bytes
      255 heads, 63 sectors/track, 2610 cylinders
      Units = cylinders of 16065 * 512 = 8225280 bytes
      Sector size (logical/physical): 512 bytes / 512 bytes
      I/O size (minimum/optimal): 512 bytes / 512 bytes
      Disk identifier: 0x9ce83f46
      
         Device Boot      Start         End      Blocks   Id  System
      /dev/sdb1               1         500     4016218+  83  Linux
      /dev/sdb2             501        1000     4016250   83  Linux
      /dev/sdb3            1001        2610    12932325    5  Extended
      /dev/sdb5            1001        1500     4016218+  83  Linux
      /dev/sdb6            1501        2610     8916043+  83  Linux
      
      Command (m for help):
      w //保存写
      
      The partition table has been altered!
      
      Calling ioctl() to re-read partition table.
      Syncing disks.
      [root@joe dev]# fdisk 
      -
      l
      
      Disk 
      /dev/sdb
      : 21.5 GB, 21474836480 bytes
      255 heads, 63 sectors/track, 2610 cylinders
      Units = cylinders of 16065 * 512 = 8225280 bytes
      Sector size (logical/physical): 512 bytes / 512 bytes
      I/O size (minimum/optimal): 512 bytes / 512 bytes
      Disk identifier: 0x9ce83f46
      
         Device Boot      Start         End      Blocks   Id  System
      /dev/sdb1               1         500     4016218+  83  Linux
      /dev/sdb2             501        1000     4016250   83  Linux
      /dev/sdb3            1001        2610    12932325    5  Extended
      /dev/sdb5            1001        1500     4016218+  83  Linux
      /dev/sdb6            1501        2610     8916043+  83  Linux
      
      Disk 
      /dev/sda
      : 21.5 GB, 21474836480 bytes
      255 heads, 63 sectors/track, 2610 cylinders
      Units = cylinders of 16065 * 512 = 8225280 bytes
      Sector size (logical/physical): 512 bytes / 512 bytes
      I/O size (minimum/optimal): 512 bytes / 512 bytes
      Disk identifier: 0x000a030a
      
         Device Boot      Start         End      Blocks   Id  System
      /dev/sda1   *           1          26      204800   83  Linux
      Partition 1 does not end on cylinder boundary.
      /dev/sda2              26         281     2048000   82  Linux swap / Solaris
      Partition 2 does not end on cylinder boundary.
      /dev/sda3             281         536     2048000   83  Linux
      Partition 3 does not end on cylinder boundary.
      /dev/sda4             536        2611    16669696    5  Extended
      /dev/sda5             536        2611    16668672   83  Linux
    5. 使用GPT分区模式分区(同时GPT的分区工具parted也可以MBR分区)
      [root@joe dev]# parted
      GNU Parted 2.1
      使用 
      /dev/sda
          //注意正在使用的是sda
      Welcome to GNU Parted! Type 'help' to view a list of commands.
      (parted) print all                                                        
      Model: VMware, VMware Virtual S (scsi)
      Disk /dev/sda: 21.5GB
      Sector size (logical/physical): 512B/512B
      Partition Table: msdos
      
      Number  Start   End     Size    Type      File system     标志
       1      1049kB  211MB   210MB   primary   ext4            启动
       2      211MB   2308MB  2097MB  primary   linux-swap(v1)
       3      2308MB  4405MB  2097MB  primary   ext4
       4      4405MB  21.5GB  17.1GB  extended
       5      4406MB  21.5GB  17.1GB  logical   ext4
      
      
      Model: VMware, VMware Virtual S (scsi)
      Disk 
      /dev/sdb:
       21.5GB
      Sector size (logical/physical): 512B/512B
      Partition Table: msdos    //sdb的应该是我们需要的gpt
      
      Number  Start  End  Size  Type  File system  标志
      
      
      警告: 无法以读写方式打开 /dev/sr0 (只读文件系统)。/dev/sr0 已按照只读方式打开。
      错误: /dev/sr0: unrecognised disk label                                   
      
      (parted) 
      select /dev/sdb
            //选择sdb                                            
      使用 /dev/sdb
      (parted) mkpart     //如果不进行gpt的选择设置,直接mkpart那么我们还是使用的MBR模式                                                      
      分区类型?  primary/主分区/extended/扩展分区? primary                     
      文件系统类型?  [ext2]? ^Z
      --------------------------------------------------------------------------------------------------
      (parted) 
      select /dev/
      sdb                                                  
      使用 /dev/sdb
      (parted) mklabel gpt                                                      
      警告: The existing disk label on /dev/sdb will be destroyed and all data on this disk will be lost. Do you
      want to continue?/Yes/否/No? yes
      (parted) print all                                                        
      Model: VMware, VMware Virtual S (scsi)
      Disk 
      /dev/sda:
       21.5GB
      Sector size (logical/physical): 512B/512B
      Partition Table: msdos
      
      Number  Start   End     Size    Type      File system     标志
       1      1049kB  211MB   210MB   primary   ext4            启动
       2      211MB   2308MB  2097MB  primary   linux-swap(v1)
       3      2308MB  4405MB  2097MB  primary   ext4
       4      4405MB  21.5GB  17.1GB  extended
       5      4406MB  21.5GB  17.1GB  logical   ext4
      
      
      Model: VMware, VMware Virtual S (scsi)
      Disk 
      /dev/sdb:
       21.5GB
      Sector size (logical/physical): 512B/512B
      Partition Table: gpt
      
      Number  Start  End  Size  File system  Name  标志
      
      
      警告: 无法以读写方式打开 /dev/sr0 (只读文件系统)。/dev/sr0 已按照只读方式打开。
      错误: /dev/sr0: unrecognised disk label                                   
      
      (parted) mkpart                                                           
      分区名称?  []? test1                                                     
      文件系统类型?  [ext2]? ext4
      起始点?
      1
                 //以1开始,默认单位是M  unit GB 指定为GB为单位                                               
      结束点? 1000M                                                           
      (parted) print                                                            
      Model: VMware, VMware Virtual S (scsi)
      Disk /dev/sdb: 21.5GB
      Sector size (logical/physical): 512B/512B
      Partition Table: gpt
      
      Number  Start   End     Size   File system  Name   标志
       1      1049kB  1000MB  999MB               test1
      
      (parted)
      rm 1
           //删除分区                                                        
      (parted) print                                                            
      Model: VMware, VMware Virtual S (scsi)
      Disk /dev/sdb: 21.5GB
      Sector size (logical/physical): 512B/512B
      Partition Table: gpt
      
      Number  Start  End  Size  File system  Name  标志
      
      (parted) mkpart                                                           
      分区名称?  []? test1                                                     
      文件系统类型?  [ext2]? ext4                                            
      起始点?0       //以0开始,出现了警告,这里是字节对齐的原因造成的,所以一般为了避免警告,我们不以0开始。                                                        
      结束点? 1000M
      警告: The resulting partition is not properly aligned for best performance.
      忽略/Ignore/放弃/Cancel? cancel                                           
      (parted) mkpart
      分区名称?  []? test1                                                     
      文件系统类型?  [ext2]? ext4                                              
      起始点?1                                                                
      结束点?1000M                                                            
      (parted) print                                                            
      Model: VMware, VMware Virtual S (scsi)
      Disk /dev/sdb: 21.5GB
      Sector size (logical/physical): 512B/512B
      Partition Table: gpt
      
      Number  Start   End     Size   File system  Name   标志
       1      1049kB  1000MB  999MB               test1
      
      (parted) mkpart                                                           
      分区名称?  []? test2                                                     
      文件系统类型?  [ext2]? ext4                                              
      起始点? 1000M                                                            
      结束点? 1500M                                                            
      (parted) print
      Model: VMware, VMware Virtual S (scsi)
      Disk /dev/sdb: 21.5GB
      Sector size (logical/physical): 512B/512B
      Partition Table: gpt
      
      Number  Start   End     Size   File system  Name   标志
       1      1049kB  1000MB  999MB               test1
       2      1000MB  1500MB  500MB               test2
      //上面是交互模式,下面是命令模式
      (parted) mkpart test3 
      1500 3000
               //使用一条命令直接搞定 分区名 起始位 结束位                                  
      警告: The resulting partition is not properly aligned for best performance.    //出现分区的原因是起始的1500和上次结束的1500重叠了。
      忽略/Ignore/放弃/Cancel? cancel         
      (parted) mkpart test3 1501M 1700M                                         
      (parted) mkpart test4 1701M 1800M                                        
      (parted) mkpart test5 1801M 1900M                                        
      (parted) print                                                            
      Model: VMware, VMware Virtual S (scsi)
      Disk /dev/sdb: 21.5GB
      Sector size (logical/physical): 512B/512B
      Partition Table: gpt
      
      Number  Start   End     Size    File system  Name   标志
       1      1049kB  1000MB  999MB                test1
       2      1000MB  1500MB  500MB                test2
       3      1501MB  1700MB  199MB                test3
       4      1701MB  1800MB  99.6MB               test4
       5      1801MB  1900MB  98.6MB               test5
      
      (parted) 
      rm 5
      
      (parted) quit
    6. 分区完以后,就是格式化和挂载分区了。也就是设置文件系统。在这里需要注意以下内容:MBR分区只能格式化主分区和扩展分区,逻辑分无不能格式化 GPT分区,在格式化以后,只能使用parted 的print查看格式结果 挂载分区:分区默认的挂载目录/mnt目录挂载点必须存在。
      [root@joe dev]#
      ls -l /dev/sdb*
      
      brw-rw----. 1 root disk 8, 16 5月   7 01:18 /dev/sdb
      brw-rw----. 1 root disk 8, 17 5月   7 01:18 /dev/sdb1
      brw-rw----. 1 root disk 8, 18 5月   7 01:18 /dev/sdb2
      brw-rw----. 1 root disk 8, 19 5月   7 01:18 /dev/sdb3
      brw-rw----. 1 root disk 8, 21 5月   7 01:18 /dev/sdb5
      brw-rw----. 1 root disk 8, 22 5月   7 01:18 /dev/sdb6
      [root@joe dev]# mkfs.ext3 
      /dev/sdb1
              //第一种设置方式
      mke2fs 1.41.12 (17-May-2010)
      文件系统标签=
      操作系统:Linux
      块大小=4096 (log=2)
      分块大小=4096 (log=2)
      Stride=0 blocks, Stripe width=0 blocks
      502944 inodes, 2008117 blocks
      100405 blocks (5.00%) reserved for the super user
      第一个数据块=0
      Maximum filesystem blocks=2059403264
      62 block groups
      32768 blocks per group, 32768 fragments per group
      8112 inodes per group
      Superblock backups stored on blocks: 
          32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632
      
      正在写入inode表: 完成                            
      Creating journal (32768 blocks): 完成
      Writing superblocks and filesystem accounting information: 完成
      
      This filesystem will be automatically checked every 23 mounts or
      180 days, whichever comes first.  Use tune2fs -c or -i to override.
      [root@joe dev]# mkfs 
      -t ext4 /dev/sdb2
              //第二种方法
      mke2fs 1.41.12 (17-May-2010)
      文件系统标签=
      操作系统:Linux
      块大小=4096 (log=2)
      分块大小=4096 (log=2)
      Stride=0 blocks, Stripe width=0 blocks
      50288 inodes, 200812 blocks
      10040 blocks (5.00%) reserved for the super user
      第一个数据块=0
      Maximum filesystem blocks=209715200
      7 block groups
      32768 blocks per group, 32768 fragments per group
      7184 inodes per group
      Superblock backups stored on blocks: 
          32768, 98304, 163840
      
      正在写入inode表: 完成                            
      Creating journal (4096 blocks): 完成
      Writing superblocks and filesystem accounting information: 完成
      
      This filesystem will be automatically checked every 26 mounts or
      180 days, whichever comes first.  Use tune2fs -c or -i to override.
      [root@joe dev]# 
      mkdir -p /mnt/joetest
          //首先建立挂载点
      [root@joe dev]# 
      mount /dev/sdb1 /mnt/joetest/
              //挂载分区
      [root@joe dev]# 
      umount /mnt/joetest/
                  //卸载挂载点
      
      上面这中挂载方式是临时的,永久性的应该如下:
      vim 
      + /etc/
      fstab
      在末尾插入一行
      
      /dev/sdb1 /mnt/imooc ext3 default 0 0
      
      设备名称    挂载点    文件系统类型
      保存退出即可
    7. swap交换分区(步骤为:建立一个普通的Linux分区,修改分区类型的16进制编码,格式化交换分区,启用交换分区。
      [root@joe dev]# 
      fdisk /dev/
      sdb
      
      WARNING: GPT (GUID Partition Table) detected on '/dev/sdb'! The util fdisk doesn't support GPT. Use GNU Parted.
      WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
               switch off the mode (command 'c') and change display units to
               sectors (command 'u').
      
      Command (m for help): p
      
      Disk /dev/sdb: 21.5 GB, 21474836480 bytes
      255 heads, 63 sectors/track, 2610 cylinders
      Units = cylinders of 16065 * 512 = 8225280 bytes
      Sector size (logical/physical): 512 bytes / 512 bytes
      I/O size (minimum/optimal): 512 bytes / 512 bytes
      Disk identifier: 0x00000000
      
         Device Boot      Start         End      Blocks   Id  System
      /dev/sdb1               1        1000     8032468+  83  Linux
      /dev/sdb2            1001        1100      803250   83  Linux
      /dev/sdb3            1101        2610    12129075    5  Extended
      /dev/sdb5            1101        1500     3212968+  83  Linux
      /dev/sdb6            1501        2610     8916043+  83  Linux
      
      Command (m for help): t
      Partition number (1-6): 
      2
             //修改ID
      Hex code (type L to list codes): L
      
       0  Empty           24  NEC DOS         81  Minix / old Lin bf  Solaris        
       1  FAT12           39  Plan 9          
      82 Linux swap
       / So c1  DRDOS/sec (FAT-
       2  XENIX root      3c  PartitionMagic  
      83 Linux
                 c4  DRDOS/sec (FAT-
       3  XENIX usr       40  Venix 80286     84  OS/2 hidden C:  c6  DRDOS/sec (FAT-
      
      
      Hex code (type L to list codes): 82
      Changed system type of partition 2 to 82 (Linux swap / Solaris)
      
      Command (m for help): w
      The partition table has been altered!
      
      Calling ioctl() to re-read partition table.
      Syncing disks.
      [root@joe dev]# fdisk 
      /dev/
      sdb
      
      WARNING: GPT (GUID Partition Table) detected on '/dev/sdb'! The util fdisk doesn't support GPT. Use GNU Parted.
      WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
               switch off the mode (command 'c') and change display units to
               sectors (command 'u').
      
      Command (m for help): p
      
      Disk /dev/sdb: 21.5 GB, 21474836480 bytes
      255 heads, 63 sectors/track, 2610 cylinders
      Units = cylinders of 16065 * 512 = 8225280 bytes
      Sector size (logical/physical): 512 bytes / 512 bytes
      I/O size (minimum/optimal): 512 bytes / 512 bytes
      Disk identifier: 0x00000000
      
         Device Boot      Start         End      Blocks   Id  System
      /dev/sdb1               1        1000     8032468+  83  Linux
      /dev/sdb2            1001        1100      803250  
      82 Linux swap /
       Solaris
      /dev/sdb3            1101        2610    12129075    5  Extended
      /dev/sdb5            1101        1500     3212968+  83  Linux
      /dev/sdb6            1501        2610     8916043+  83  Linux
      
      Command (m for help): q
      
      [root@joe dev]# mkswap 
      /dev/sdb2
          //设置交换区
      Setting up swapspace version 1, size = 803244 KiB
      no label, UUID=c7d31434-4013-4bbb-b68e-29b501934377
      [root@joe dev]# swapon 
      /dev/sdb2
          //开启交换区
      [root@joe dev]# free
                   total       used       free     shared    buffers     cached
      Mem:       1030612     132468     898144          0      13612      51388
      -/+ buffers/cache:      67468     963144
      Swap:      
      2851232 0 2851232
      
      [root@joe dev]# swapoff 
      /dev/sdb2
          //关闭交换区
      [root@joe dev]#
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  • 原文地址:https://www.cnblogs.com/zi-xing/p/4483027.html
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