jsqwang · August 29, 2015 14:23
diff --git a/swap.sh b/swap.sh
 #If you want to learn how to create the file faster, remove the file and follow along below:

 sudo rm /swapfile

 #The Faster Way

 #The quicker way of getting the same file is by using the fallocate program. This command creates a file of a preallocated size #instantly, without actually having to write dummy contents.

 #We can create a 4 Gigabyte file by typing:

 sudo fallocate -l 4G /swapfile

 #The prompt will be returned to you almost immediately. We can verify that the correct amount of space was reserved by typing:

 ls -lh /swapfile

 # -rw-r--r-- 1 root root 4.0G Apr 28 17:19 /swapfile

 # As you can see, our file is created with the correct amount of space set aside.

 # Enabling the Swap File
 # Right now, our file is created, but our system does not know that this is supposed to be used for swap. We need to tell our   #system to format this file as swap and then enable it.

 # Before we do that though, we need to adjust the permissions on our file so that it isn't readable by anyone besides root.  #Allowing other users to read or write to this file would be a huge security risk. We can lock down the permissions by typing:

 sudo chmod 600 /swapfile

 #Verify that the file has the correct permissions by typing:

 ls -lh /swapfile

 #-rw------- 1 root root 4.0G Apr 28 17:19 /swapfile

 #As you can see, only the columns for the root user have the read and write flags enabled.

 #Now that our file is more secure, we can tell our system to set up the swap space by typing:

 sudo mkswap /swapfile

 #Setting up swapspace version 1, size = 4194300 KiB
 #no label, UUID=e2f1e9cf-c0a9-4ed4-b8ab-714b8a7d6944

 #Our file is now ready to be used as a swap space. We can enable this by typing:

 sudo swapon /swapfile

 #We can verify that the procedure was successful by checking whether our system reports swap space now:

 sudo swapon -s

 # Filename                Type        Size    Used    Priority
 # /swapfile               file        4194300 0       -1

 #We have a new swap file here. We can use the free utility again to corroborate our findings:

 free -m

 #             total       used       free     shared    buffers     cached
 # Mem:          3953        101       3851          0          5         30
 # -/+ buffers/cache:         66       3887
 # Swap:         4095          0       4095

 #Our swap has been set up successfully and our operating system will begin to use it as necessary.

 #Make the Swap File Permanent
 #We have our swap file enabled, but when we reboot, the server will not automatically enable the file. We can change that though #by modifying the fstab file.

 #Edit the file with root privileges in your text editor:

 sudo nano /etc/fstab

 # At the bottom of the file, you need to add a line that will tell the operating system to automatically use the file you created:
 

 /swapfile   none    swap    sw    0   0


 # Save and close the file press Control + X, then Y to "YES", then ENTER when you are finished.
	#If you want to learn how to create the file faster, remove the file and follow along below:

	sudo rm /swapfile

	#The Faster Way

	#The quicker way of getting the same file is by using the fallocate program. This command creates a file of a preallocated size #instantly, without actually having to write dummy contents.

	#We can create a 4 Gigabyte file by typing:

	sudo fallocate -l 4G /swapfile

	#The prompt will be returned to you almost immediately. We can verify that the correct amount of space was reserved by typing:

	ls -lh /swapfile

	# -rw-r--r-- 1 root root 4.0G Apr 28 17:19 /swapfile

	# As you can see, our file is created with the correct amount of space set aside.

	# Enabling the Swap File
	# Right now, our file is created, but our system does not know that this is supposed to be used for swap. We need to tell our #system to format this file as swap and then enable it.

	# Before we do that though, we need to adjust the permissions on our file so that it isn't readable by anyone besides root. #Allowing other users to read or write to this file would be a huge security risk. We can lock down the permissions by typing:

	sudo chmod 600 /swapfile

	#Verify that the file has the correct permissions by typing:

	ls -lh /swapfile

	#-rw------- 1 root root 4.0G Apr 28 17:19 /swapfile

	#As you can see, only the columns for the root user have the read and write flags enabled.

	#Now that our file is more secure, we can tell our system to set up the swap space by typing:

	sudo mkswap /swapfile

	#Setting up swapspace version 1, size = 4194300 KiB
	#no label, UUID=e2f1e9cf-c0a9-4ed4-b8ab-714b8a7d6944

	#Our file is now ready to be used as a swap space. We can enable this by typing:

	sudo swapon /swapfile

	#We can verify that the procedure was successful by checking whether our system reports swap space now:

	sudo swapon -s

	# Filename Type Size Used Priority
	# /swapfile file 4194300 0 -1

	#We have a new swap file here. We can use the free utility again to corroborate our findings:

	free -m

	# total used free shared buffers cached
	# Mem: 3953 101 3851 0 5 30
	# -/+ buffers/cache: 66 3887
	# Swap: 4095 0 4095

	#Our swap has been set up successfully and our operating system will begin to use it as necessary.

	#Make the Swap File Permanent
	#We have our swap file enabled, but when we reboot, the server will not automatically enable the file. We can change that though #by modifying the fstab file.

	#Edit the file with root privileges in your text editor:

	sudo nano /etc/fstab

	# At the bottom of the file, you need to add a line that will tell the operating system to automatically use the file you created:


	/swapfile none swap sw 0 0


	# Save and close the file press Control + X, then Y to "YES", then ENTER when you are finished.