You want the total available memory to be greater. What can you do?
You may want to resize your VM, or upgrade the physical server, to have more RAM.
Click here for AWS resizing directions or here for GCP resizing directions. If you have ample hard disk space but insufficient memory, you may want to see this posting for directions for adding or configuring virtual memory. If you want a Bash script to create swap space, see this posting.
To buy physical RAM chips for your physical server, see this external link. When purchasing physical memory, consider the differences of the bus speed between the varieties you may purchase. This will affect performance.
We are reminded that memory is much more affordable than it used to be by this quote: "…memory rents for about $12 per kilobyte per month…" taken from page 98 to The Mythical Man-Month.