1, use the partition:
When the OS is installed, a dedicated swap partition is created, and the size of the space must be planned in advance and mount automatically when the system is booted.
This method can only be set when the OS is installed, and once the settings are changed very hard, unless the system is reinstalled.
2. Use Swapfile: (or the entire free partition)
Create a new temporary swapfile or an idle partition, set to swap space when needed, and add up to 8 swapfile.
The size of the swap space, closely related to the CPU, can use up to 2GB of space in the i386 system.
After the system starts, the total capacity of the 2G is increased or decreased as required.
This method is more flexible, but also more convenient, the disadvantage is to start the system after manual setup.
Here are the steps to use Swapfile to increase swap space:
The commands involved:
Free---View the memory status command to display the size and usage of the memory,swap,buffer cache;
DD---read, convert and output data commands;
Mkswap---setting swap area
Swapon---Enable swap area, equivalent to mount
Swapoff---Closed swap area, equivalent to Umount
Steps:
1. Create Swapfile:
Under Root, create swapfile, assuming the current directory is "/", execute the following command:
# dd If=/dev/zero of=swapfile bs=1024 count=500000
A swapfile is created in the root directory with the name "Swapfile", the size is 500M, and the file can be exported to any directory you want.
Personal feel or directly placed in the root directory is better, at a glance, not easy to damage, put in other directories is not;
The options in the command explain:
---of: the path and name of the output interchange file;
---BS: block size, unit byte, generally 1k or 1024 byte;
---count: The total number of blocks is the total size of space, in blocks that are k;
---if: Read the source of free space, why is zero, not clear, first fixed so write it;
2. Set the Swapfile to swap space
# Mkswap Swapfile
3. Enable Swap space, this operation is somewhat similar to the mount operation (personal understanding):
# Swapon Swapfile
Now that the swap space has been increased, you can use the free command to see if the size of the swap space has changed;
4, if no longer use space can choose to turn off swap space, this operation is somewhat similar to the umount operation (Personal understanding)::
# Swapoff Swapfile
Using this method in each system startup requires manual setup, Swapfile, more trouble, workaround:
Append the following to the last line of the/etc/rc.d/rc.local file: (edit this file, of course, with VI ~)
/sbin/swapon/swapfile
Save and exit so that the swap space will automatically load after the system starts;
Summary: In the installation of the OS must be planned after the swap size, usually twice times the memory, but to consider the possibility of increasing memory later, so you can consider setting a little larger, want to install oracle10g in the virtual machine, found that the default swap space does not meet the minimum requirements, Because I allocate the physical memory is 1G, then need to follow the requirements of 2G swap swap space, the default is only 1G swap space.
The steps to add swap space are as follows:
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
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 in
2048000+0 Records out
2097152000 bytes (2.1 GB) copied, 272.867 seconds, 7.7 mb/s
Step Three: Create (set) Swap space, use command Mkswap
[Email protected] image]# Mkswap/opt/image/swap
Setting up Swapspace version 1, size = 2097147 KB
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
Fifth step: Start the newly added 2G swap space, using the command swapon
[Email protected] image]# Swapon/opt/image/swap
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
Seventh Step: Modify the/etc/fstab file so that the newly added 2G swap space automatically takes effect after the system restarts
At the end of the document, add:
/opt/image/swap swap swap defaults 0 0
My actions
[[email protected] server]# free
Total used free shared buffers Cached
mem:1785856 1753452 32404 0 38592 1036312
-/+ buffers/cache:678548 1107308
swap:2064376 116 2064260
Create swap space file, 1000M
[[email protected]/]# dd If=/dev/zero of=/swapfile bs=1024 count=1000000
1000000+0 Records in
1000000+0 Records out
1024000000 bytes (1.0 GB) copied, 28.5423 seconds, 35.9 MB/s
[Email protected]/]# Mkswap swapfile
Setting up Swapspace version 1, size = 1023995 KB
[[email protected]/]# swapon Swapfile Open
[[email protected]/] #swapoff swapfile off
Delete
Swapoff Swapfile
RM-RF Swapfile
This article is from the "vmware/oracle" blog, make sure to keep this source http://123124432.blog.51cto.com/12616119/1904432
Not enough swap space solution in Linux6