I have standard 250 mb of swap space in ubuntu and i want to expand it to a bigger size I need 800 mb which i think will be enough to open several applications without having to hit the current swap limit I hope someone will help me out

Best Answer

You can always create a swap file to add more swap space. This is not the same in every aspect as swap partition, but it will be easy and dynamic.

In the following steps, change /media/fasthdd/swapfile.img to anything you like. For example, it can be /swap.img as well. /media/fasthdd/swapfile.img is just an example filename. If you are using this one, then of course there must be a directory /media/fasthdd/ with enough free space for your new swap file.

Use any terminal program to run the commands of the following steps All commands should be run with root privileges . To do this, you can either add sudo to the beginning of every command or run sudo bash before running the commands.

Create an empty file:

This file will contain virtual memory so make it big enough to handle your needs This one will create a 1GiB file, which means +1GiB swap space for your system.
```
dd if=/dev/zero of=/media/fasthdd/swapfile.img bs=1024 count=1M
```
If you want to make a 3GiB file, then change count value to count=3M . See man dd for more information.
Bake the swap file:

The following command will put a swap filesystem into your fresh swap file
```
mkswap /media/fasthdd/swapfile.img
```
Bring up on boot:

To make sure that your new swap space is activated while booting up computer, you should add it to the filesystem configuration file /etc/fstab . Add this to the end of the file This is recommended because other filesystems ( at least one that contains a swap file ) must be mounted in read-write mode before we can access any files.
```
# Add this line to /etc/fstab
/media/fasthdd/swapfile.img swap swap sw 0 0
```
Activate:

You can either start the computer or activate the new swap file by hand with the following command
```
swapon /media/fasthdd/swapfile.img
```

If everything goes well , you should see that more swap space is available for use. You can use the following commands to check your new swap and confirm that it is active

$ cat /proc/swaps
Filename                           Type       Size    Used    Priority
/media/fasthdd/swapfile.img        file       8388604 2724    -1

$ grep 'Swap' /proc/meminfo
SwapCached:         4772 kB
SwapTotal:       8388604 kB
SwapFree:        8355812 kB