I've been provisioning a pile of tiny VPSes (from Digital Ocean) for tiny web services for the last few weeks. While tuning one such site, I made an incorrect assumption that caused MySQL to fall over: Digital Ocean boxes default to having no swap space.

Assuming you want a little bit of leeway in your memory limits, it is easy to add some swap:

# Create a 1GB blank disk image.
dd if=/dev/zero of=/var/swap.img bs=1M count=1024

# Activate it as swap space.
mkswap /var/swap.img
swapon /var/swap.img

# Set it to activate at startup.
echo "/var/swap.img    none    swap    sw    0    0" >> /etc/fstab