How Red Hat Linux increases swap space

Follow the steps to explain how Red Hat Linux increases swap space

Method/Step

1. First step: Make sure there is enough space in the system for swap swap space, I am using KVM, ready to add a swap file to a separate file system, add 2G swap files to/opt/image

2. Step two: Add the swap file and set its size to 2G, using the following command

   [[email protected] image]# dd If=/dev/zero of=/opt/image/swap bs=1024 count=2048000

   After a while, the following results are returned:

   2048000+0 Records in2048000+0 Records out2097152000 bytes (2.1 GB) copied, 272.867 seconds, 7.7 mb/s

3. Step Three: Create (set) Swap space, use command Mkswap

   [Email protected] image]# Mkswap/opt/image/swap

   Setting up Swapspace version 1, size = 2097147 KB

4. Fourth step: Check the size of the existing swap space and use the command free

   
   

   
   

   [Email protected] image]# free-m

   
   

   Total used free shared buffers Cached
   mem:1011 989 21 0 1 875
   -/+ buffers/cache:112 898
   swap:1027 0 1027

   
   

   Or check the Meminfo file grep swaptotal/proc/meminfo

   
   

5. Fifth step: Start the newly added 2G swap space, using the command swapon

6. [Email protected] image]# Swapon/opt/image/swap

7. Sixth step: Confirm that the newly added 2G swap space is in effect, use the command free

   
   

   
   

   [[email protected] image]# free-m

   
   

   Total used free shared buffers Cached
   mem:1011 995 15 0 4 877
   -/+ buffers/cache:113 897
   swap:3027 0 3027

   
   

   Or check the Meminfo file grep swaptotal/proc/meminfo

   
   

8. Seventh Step: Modify the/etc/fstab file so that the newly added 2G swap space automatically takes effect after the system restarts

   Added at the end of the document:/opt/image/swap swap defaults 0 0