Allocate swap after Ubuntu 14.04 LTS installation
Solution 1
First, to create 4,000 MB of swap space:
$ sudo dd if=/dev/zero of=/swapspace bs=1M count=4000
4000+0 records in
4000+0 records out
4194304000 bytes (4.2 GB) copied, 5.92647 s, 708 MB/s
or
$ sudo fallocate -l 4000M /swapspace
Next turn it into a usable swap file:
$ sudo mkswap /swapspace
Setting up swapspace version 1, size = 4095996 KiB
no label, UUID=7d1895e4-7ccf-42c6-979a-51ebddb49e91
Activate it:
$ sudo swapon /swapspace
Confirm active swap spaces:
$ cat /proc/swaps
Filename Type Size Used Priority
/swapspace file 4095996 0 -1
Next, add the following line to /etc/fstab to activate the new swap at boot:
/swapspace none swap defaults 0 0
See also this wiki page: https://help.ubuntu.com/community/SwapFaq
Solution 2
To answer your question indirectly, you don't need to manage swapfiles yourself. There is a package called swapspace which will dynamically add swap files as needed.
- sudo apt-get install swapspace
Then you are done. Your system will grow and shrink swap space as needed.
Solution 3
Follow these steps:
sudo dd if=/dev/zero of=/mnt/{filename}.swap bs=1M count={swap_size}
sudo mkswap /mnt/{filename}.swap
sudo swapon /mnt/{filename}.swap
sudo gedit /etc/fstab
- Add the following text at the end of the file,
/mnt/{filename}.swap none swap sw 0 0
Note: Replace {filename} with any name you want to set to the file and replace {swap_size} with the size you want to assign to the swap file. Be sure the size of the file must the twice larger than the memory size.
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Ahsan Hussain
Updated on September 18, 2022Comments
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Ahsan Hussain over 1 year
I've installed Ubuntu 14.04 LTS about one month ago, I'm dual booting Ubuntu 14.04 LTS and Windows 8.1.
I didn't create any swap space while installation but now I really need to add this for Ubunutu. I tried checking for any assigned swap space by using
sudo swapon -s
and I got empty headers like shown below:ahsan@ahsan-Inspiron-N5110:~$ sudo swapon -s Filename Type Size Used Priority
Then I tried to allocate some swap space using
dd of=output.dat bs=1 seek=390143672 count=0
and the output was:0+0 records in 0+0 records out 0 bytes (0 B) copied, 0.000170607 s, 0.0 kB/s
I also tried the command
sudo dd if=/dev/zero of=/swapfile bs=1G count=4
and output was:dd: memory exhausted by input buffer of size 1073741824 bytes (1.0 GiB)
Then I tried
sudo fallocate -l 4G /swapfile
but output was:fallocate: /swapfile: fallocate failed: Operation not supported
I aslo checked my hard drives following is my hard drive structure:
ahsan@ahsan-Inspiron-N5110:~$ df -h Filesystem Size Used Avail Use% Mounted on /dev/sda2 99G 18G 77G 19% / none 4.0K 0 4.0K 0% /sys/fs/cgroup udev 1.4G 4.0K 1.4G 1% /dev tmpfs 286M 1.2M 284M 1% /run none 5.0M 0 5.0M 0% /run/lock none 1.4G 24M 1.4G 2% /run/shm none 100M 56K 100M 1% /run/user
And the output of
free -m
is:ahsan@ahsan-Inspiron-N5110:~$ free -m total used free shared buffers cached Mem: 2850 2665 184 421 25 846 -/+ buffers/cache: 1794 1055 Swap: 0 0 0
Please show me how can I add the swap without affecting any data of mine. I've installed 64 bit Ubuntu LTS and have 3GB of RAM and a 500GB hard drive.
I have been to this Ask Ubuntu question and I tried the commands and the output is:
ahsan@ahsan-Inspiron-N5110:~$ sudo dd if=/dev/zero of=/swapspace bs=1G count=4 4+0 records in 4+0 records out 4294967296 bytes (4.3 GB) copied, 47.1951 s, 91.0 MB/s ahsan@ahsan-Inspiron-N5110:~$ sudo dd if=/dev/zero of=/swapspace bs=1G count=4sudo mkswap /swapspace dd: invalid number ‘4sudo’ ahsan@ahsan-Inspiron-N5110:~$
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shellter over 9 yearsThe clue was in the error message
dd: invalid number '4sudo'
, right? I would guess you had a copy/paste problem. Glad you got your problem solved! In the future, read those error messages carefully and try to figure out why you're getting that message!;-) Good luck.
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Ahsan Hussain over 9 yearssorry i mistakenly tried to run command twice, i think its worked for me :) now also showing swap in system monitor.. Thanks alot
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Ahsan Hussain over 9 yearsi restarted the machine and the swap is gone, its again not available
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nyuszika7h over 9 yearsThe "running out of memory" part should be added to the answer. Comments are meant to be transient, they may be deleted.
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nyuszika7h over 9 years"Be sure the size of the file must the twice larger than the memory size." That advice no longer holds nowadays unless you're really low on memory (say, 1 GB or less). If you want to use hibernation, you'll need at least the amount of physical memory as swap, but there's no reason to have 8 GB swap if you have 4 GB RAM.
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Wolverine over 9 yearsYour suggestion is considered.
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LOG_TAG over 7 yearssudo apt-get install swapspace is best option compare to allocating like this?