Free Mail Server on OCI – Swapfile

This is the series of articles about how to setup free own mailserver on OCI.

• Free Mail Server on OCI – Oracle Cloud Account
• Free Mail Server on OCI – Your Domain Name
• Free Mail Server on OCI – IPv4 Address, PTR
• Free Mail Server on OCI – Data Block Volume
• Free Mail Server on OCI – Virtual Cloud Network
• Free Mail Server on OCI – Compute Instance
• Free Mail Server on OCI – Swapfile
• Free Mail Server on OCI – Firewalld, OCFS2
• Free Mail Server on OCI – Docker, Cron, Certbot
• Free Mail Server on OCI – Docker-Mailserver

Swapfile

Even if you have great amount of memory allocated to your VM instance, it is still advised to create a swapfile and mount it to your VM.

For VM instances with 16GB of memory or more it is advised to create at least 4GB of swapfile, I have only 12GB of memory but I still think 4GB of swapfile will be beneficial. Run the following commands:

# Create swapfile
sudo dd if=/dev/zero of=/swapfile bs=1M count=4000 status=progress

# Change the CHMOD for swapfile
sudo chmod 0600 /swapfile

# Make SWAP
sudo mkswap /swapfile

# Enable SWAP
sudo swapon /swapfile

# Add the SWAP record to FSTAB
echo "/swapfile swap swap defaults 0 0" | sudo tee -a /etc/fstab

# Remount FSTAB
sudo mount -a

If everything went OK, by running the free command you should see your SWAP (bottom line):

ubuntu@mailserver:~$ free
               total        used        free      shared  buff/cache   available
Mem:        12226604      238280    11296260        4484      692064    11790644
Swap:        4095996         264     4095732

Let’s configure OCFS2, more details you can read on official Oracle documentation (this page, and this page). Follow this article.