Edit: More info for anyone that happens to find this thread. My main concern here was what would happen if I ever needed to restore from backups and didn't have a system/artifacts directory. I decided to try it for myself since my setup isn't mission critical. When I tested my backups this week, everything worked fine. TeamCity even created the missing system/artifacts directory automatically.
I was reading the documentation and it looks like TeamCity is designed so the server administrator can delete artifacts directly from the filesystem. So far, I noticed I lose the following extra build info:
Build Parameters - Actual Parameters on Agent
Maven Build Info
Is there anything that I'm overlooking? I'm thinking about removing system/artifacts from my backups, so if anyone knows about anything I should be careful of, please let me know. I don't care if I lose the actual artifacts.