Into one of my posts (How to install Ghost on Ubuntu 16.04) I mentioned that error
Killedt:iconv-lite → gunz may occur because of using
npm on VPS instance with low RAM. I’ve got such error while installing Ghost on VPS instance with 512MB of RAM. That happened because
npm run out of memory and Linux OOM killer started to kill processed to get memory back to the system. Such problem could be resolved by increasing RAM from 512MB to 1GB or by creating a swap file.
In this tutorial I will describe how to add a swap file on Ubuntu 16.04.
Create a file for swapping
We’ll store the swap file in
/var/swap/ folder. So let’s create required folders first.
sudo mkdir -p /var/swap
Now let’s create a swap file
cd /var/swap sudo touch swap.img sudo chmod 600 swap.img
We created a file which will be used for swapping and restricted file’s permissions to
write only for file’s owner (
root in that case).
Swap file size
According to some sources it’s recommended to create a swap with size
2X of instance RAM. But in case of Ghost 512Mb of RAM should be enough.
Lets change file’s size to 512MB
sudo dd if=/dev/zero of=/var/swap/swap.img bs=1024k count=512
The output will look like
512+0 records in 512+0 records out 536870912 bytes (537 MB, 512 MiB) copied, 1.03334 s, 520 MB/s
We are using a
dd utility which fills a swap file with zeroes to required size (in our case it’s 512Mb) with blocks size equal to
1024k. Creating swap file with such parameters should not take too long.
Set up a swap area
Our file for swapping is ready. Now we need to set up a swap area on our created file.
sudo mkswap /var/swap/swap.img
Our swap area is ready for use. Now let’s enable it
sudo swapon /var/swap/swap.img
swapon is an utility which permanently enables swap. After system reboot it will be disabled. To make swap constantly enabled we should add the following line into the file
# Swap file /var/swap/swap.img none swap sw 0 0
/etc/fstab is a config file which contains information about how file systems and devices will be mounted and used during system boot.