Right, but again, what good does the spacer file do if you're not aware that you're running low on disk space? That is: if your monitoring isn't working, how do you know that you need to quickly make room?

And if your monitoring is working correctly, the spacer file really serves no purpose other than lowering the available disk space.

1. When your DBMS is no longer responding to queries, your boss and your customers replace your monitoring system (unlimited free phone calls 24/7 included ;). Case in point: HN is often a better place to check than Google Cloud status page, for example.

2. Maybe you didn't get it, but "nullmailer not forwarding cron email due to mailgun problems" was a bit too specific to be an example I just made up, wasn't it? Again, the premise "if your monitoring is working correctly" is not a good one to base your reasoning upon. Especially if you have 1 VM (VPS) and not a whole k8s cluster with a devops team with rotational on-call assignments.

The reason was, I thought, discussed in the article.

When you actually fill up your disc, many linux commands will simply fail to run, meaning getting out of that state is extremely difficult. Deleting the file means you have room to move files around / run emacs / whatever, to fix the problem.

Somebody will notify you. If the service is just for yourself, you don't need monitoring at all.

Yes, yes, but they will notify you after your service is down (because that's when they notice), in part thanks to a spacer file that eats up available disk space without being of any use. A monitoring service would notify you before your service is down, users grab pitchforks and start looking for torches.

I understand the benefit to be able to quickly delete some file to be able to run some command that would need space, though I find that highly theoretical. If it's your shell that requires space to start, you won't be able to run the command to remove the spacer, and once you're in the shell, I've never found it hard to clean up space; path autocompletion is the only noticeable victim usually. And at this point, the services are down anyhow, and you likely don't want to restart them before figuring out what the problem was, so I don't see the point of quickly being able to make some room.

It feels like "having two flat tires at the same it is highly unlikely, so I always drive with a flat tire just to make sure I don't get an unforeseen flat tire". It's cute, but I'd look for a new job if anyone in the company suggested that unironically.

This is an additional safety net. It's like doing backups. Of course you should replace your hard drive before the other drive breaks down, but you want to have a backup in case your server burns down.

because sometimes you run things that don't really need monitoring.

I run bunch of websites for pet projects and for friends clubs etc. They don't need monitoring, and even if they go down for couple of hours (or days) doesn't really matter.

I do monitor them, but mostly as an excuse to test various software, that I don't get you use during my day job (pretty sure that bunch of static sites and low use forums don't need elstic cluster, for log storage :) )

And sometims you simply don't have the time to deal with this right now. So you do a quick hack, and do it later.