Disk Space
Domain: Installation & Setup
Motivation
Hermes and its dependencies need a few hundred megabytes of disk space. If your drive is almost full, the install may fail. Make sure you have at least 1 GB free.
Concrete Example
You check with df -h and see you have 5 GB free. Plenty. The install finishes without issue.
Analogy
Like checking your bag has room before buying groceries. No space, no room for the food.