centos系统swap设置查看swap分区的方法

曾经终败给现在 2021-11-05 10:24 436阅读 0赞

交换分区swap，意思是“交换”、“实物交易”，它的功能就是在内存不够的情况下，操作系统先把内存中暂时不用的数据，存到硬盘的交换空间，腾出内存来让别的程序运行，和Windows的虚拟内存（pagefile.sys）的作用是一样的。

**查看 已存在的swap分区：**

[?][Link 1]

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      <code>[root@iZ94hzx4xerZ bin]</code> 
      <code># swapon -s </code> 
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       &nbsp; 
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      <code>Filename Type Size Used Priority </code> 
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       &nbsp; 
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      <code>/mnt/swap</code> 
      <code>file</code> 
      <code>10232 10184 -1 </code> 
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**创建用于交换分区的文件：**

[?][Link 1]

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      <code>[root@iZ94hzx4xerZ bin]</code> 
      <code># dd if=/dev/zero of=/mnt/swap bs=1024 count=10240 </code> 
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       &nbsp; 
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      <code>10240+0 records </code> 
      <code>in</code> 
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       &nbsp; 
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      <code>10240+0 records out </code> 
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      <code>10485760 bytes (10 MB) copied, 0.237175 s, 44.2 MB</code> 
      <code>/s</code> 
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bs=1024 指的是创建swap分区的初始大小，count指的是swap最大空间，推荐设置为内存的1-2倍。

**设置交换分区文件：**

[?][Link 1]

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      <code>[root@iZ94hzx4xerZ mnt]</code> 
      <code># mkswap /mnt/swap </code> 
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       &nbsp; 
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      <code>mkswap: </code> 
      <code>/mnt/swap</code> 
      <code>: warning: don't erase bootbits sectors </code> 
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      <code>on whole disk. Use -f to force. </code> 
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       &nbsp; 
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      <code>Setting up swapspace version 1, size = 2044 KiB </code> 
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       &nbsp; 
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      <code>no label, UUID=e6f0ae06-0e6b-4fce-8c18-d5a247b40259 </code> 
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**立即启用交换分区文件：**

[?][Link 1]

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      <code>[root@iZ94hzx4xerZ mnt]</code> 
      <code># swapon /mnt/swap </code> 
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**设置开机时自启用swap分区：**

需要修改文件/etc/fstab中的swap行。

添加 /mnt/swap swap swap defaults 0 0

[?][Link 1]

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      <code># </code> 
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      <code># /etc/fstab </code> 
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      <code># Created by anaconda on Thu Aug 14 21:16:42 2014 </code> 
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      <code># </code> 
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      <code># Accessible filesystems, by reference, are maintained under '/dev/disk' </code> 
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      <code># See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info </code> 
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      <code># </code> 
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      <code>UUID=94e4e384-0ace-437f-bc96-057dd64f42ee / ext4 defaults,barrier=0 1 1 </code> 
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       &nbsp; 
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      <code>tmpfs </code> 
      <code>/dev/shm</code> 
      <code>tmpfs defaults 0 0 </code> 
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       &nbsp; 
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      <code>devpts </code> 
      <code>/dev/pts</code> 
      <code>devpts gid=5,mode=620 0 0 </code> 
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       &nbsp; 
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      <code>sysfs </code> 
      <code>/sys</code> 
      <code>sysfs defaults 0 0 </code> 
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       &nbsp; 
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      <code>proc </code> 
      <code>/proc</code> 
      <code>proc defaults 0 0 </code> 
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       &nbsp; 
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      <code>/mnt/swap</code> 
      <code>swap swap defaults 0 0 </code> 
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**设置后可以执行free -m命令或者top查看效果：**

[?][Link 1]

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      <code>[root@iZ94hzx4xerZ bin]</code> 
      <code># top </code> 
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      <code>top</code> 
      <code>- 20:33:11 up 4:53, 2 </code> 
      <code>users</code> 
      <code>, load average: 0.00, 0.00, 0.00 </code> 
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       &nbsp; 
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      <code>Tasks: 104 total, 1 running, 88 sleeping, 15 stopped, 0 zombie </code> 
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       &nbsp; 
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      <code>Cpu(s): 0.3%us, 0.2%sy, 0.0%ni, 99.5%</code> 
      <code>id</code> 
      <code>, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st </code> 
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       &nbsp; 
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      <code>Mem: 1920740k total, 1845096k used, 75644k </code> 
      <code>free</code> 
      <code>, 38716k buffers </code> 
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       &nbsp; 
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      <code>Swap: 10232k total, 10184k used, 48k </code> 
      <code>free</code> 
      <code>, 260692k cached </code> 
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**删除swap分区：**

[?][Link 1]

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      <code>[root@iZ94hzx4xerZ bin]</code> 
      <code># swapon /mnt/swap</code> 
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转载于:https://www.cnblogs.com/pythonClub/p/10423703.html

[Link 1]: https://www.jb51.net/os/RedHat/514512.html#