Is it unhealthy for SSD if I write 'vital signal' to check a python code is running?

Solution 1:

Doing that will degrade the SSD and destroy it over time.

In my last job, the SSD health tool (smartctl) indicated that the 15 SSDs in our cluster product were wearing rapidly and had only months of life left. The team found that a third party software package (etcd) was syncing a small amounts of data to a filesystem on SSD once per second. And each sync wrote at least an entire 16K block. Luckily, the problem was found early enough that we could patch it in a software update before suffering too many customer returns.

Write the 'vitality' file somewhere else. It could be on a tmpfs like /var/run/user/. Or use a different vitality mechanism; something like supervisord can manage your task, run health checks and restart it on failure.