Saving global settings never completes at ~2000 sites

Environment
16-core host. ~2000 sites configured.

Steps to reproduce

1. Run an instance with ~2000 sites configured.
2. Go to and change "Get attack IP from".
3. Click Save.

Expected behavior
The setting is saved, or the save fails with a visible error.

Actual behavior
The request hangs and never completes. No error is shown. Reopening the page shows the
previous value, so the change was never applied.

Additional context
Applying a global setting rewrites the config file for every site. At ~2000 sites a full pass
takes about 37 minutes. While it runs, sites-enabled is emptied and then refilled, so the
number of files on disk drops by hundreds before climbing back

We’ve already submitted this as a feature request.

Generally, we don’t see many cases where a single SafeLine instance is managing this many sites. When users have this many sites, they often deploy multiple SafeLine instances to manage them separately.