Hello one and all
I just want to know the best way to have a swap file on an already in use 1Tb hard drive on my Raspberry Pi 3.

Start with How_To_Ask_a_Question then we might all get somewhere.

Thank you for responding. I use a rpi3 with raspian pixel installed on a 64Gb micro sd. Also attached via usb a one terabyte external hard drive with much data mainly raw .dv files that I am gradually converting to .mp4 files using ffmpeg. I do not have any means to back it up at present. That is not the problem. The problem is mainly when using Chromium web browser. If I open too many tabs my Rasperry Pi hangs and I have to unplug it and re start. I know this is not good. I think if there is some way to be able to have a swap file on the external hard drive may solve my problem.

You might want to read some threads on the subject as it depends on what distribution your running on the Pi.

http://raspberrypimaker.com/adding-s...e-raspberrypi/
https://raspberrypi.stackexchange.co...wap-space#1605

To create swap file:

Determine the size of the new swap file in megabytes and multiply by 1024 to determine the number of blocks. For example, the block size of a 64 MB swap file is 65536.

At a shell prompt as root, type the following command with count being equal to the desired block size:
dd if=/dev/zero of=/path/to/swapfile bs=1024 count=65536

Setup the swap file with the command:
mkswap /path/to/swapfile

To enable the swap file immediately but not automatically at boot time:
swapon /path/to/swapfile

To enable at boot see the first link.

If the system is using lots of swap i.e. check the output of the free command then adding more may not help.

Many thanks for your reply.
I have been trying to understand this but the output I get is "dd: failed to open ‘/media/pi/exttosh/swapfile.img’: Is a directory" and yes I do have root. It does not seem to matter if the name is swap.file, swapfile or swapfile.img.
I don't know where I'm going wrong and got to take a break now.

If it helps you can change to that specific directory on the USB drive i.e.

cd /media/pi/exttosh

And then just create the file.

dd if=/dev/zero of=swapfile bs=1024 count=65536

1 members found this post helpful.

Thank you michaelk.
Success at last I now have a large swap file on my external drive and I can open many tabs in the Chromium browser without my Pi hanging. I will now try this on my Pine64. I am grateful thanks again.