Amazon EC2: Adding Swap
Andrew B. Collier
So, after upgrading to R 3.2.0 on my EC2 instance, I was installing newer versions of various packages and I ran into a problem with dplyr: virtual memory exhausted!
Seemed like a good time to add some swap.
Adding Swap and Turning it On
First make some swap files. I am in favour of creating a few smaller swap files rather than a single monolithic one.
sudo dd if=/dev/zero of=/var/swap.1 bs=1M count=1024 sudo dd if=/dev/zero of=/var/swap.2 bs=1M count=1024 sudo dd if=/dev/zero of=/var/swap.3 bs=1M count=1024
Another way to create swap files is by using
fallocate, which actually provides a more intuitive interface.
sudo fallocate -l 1G /var/swap.1
To make sure that these files are secure, change the access permissions.
sudo chmod 600 /var/swap.
Next you’ll set up a swap area on each of these files.
sudo /sbin/mkswap /var/swap.1 sudo /sbin/mkswap /var/swap.2 sudo /sbin/mkswap /var/swap.3
Finally activate as many of the swap files as you require to give you sufficient virtual memory. I just needed one for starters.
sudo /sbin/swapon /var/swap.1
If you want the swap space to be activated again after reboot then you will need to add an entry to
/etc/fstab. More information can be found here.
Turning it Off Again
When you are done with the memory intensive operations you might want to disable the swap files.
sudo /sbin/swapoff /var/swap.1
Here’s everything in a Gist (using just a single swap file and setting its size from an environment variable).