Here are 3 "funny" bugs, and 5 improvement proposals for a change:
We do daily off-site backups of all virtual servers on one of our shared hosts using Virtualmin's built-in scheduled backup function.
1) BUG: Yesterday a user with a reseller account wanted to change one of his customer (actually was a family) site's quota from 500 MB to 1 GB (the disk usage was like 498 MB), but he forgot to change the drop-down from "MB" to "GB". He could save successfully without any warning the new quota of 1 MB, even if it was already way exceeded by the use. No emails received either, as quota was already way over. I think at least a warning should be made, and probably a new quota BELOW the use or below use + threshold for warnings should be refused and generate an error at saving, to avoid such bugs to start with.
2) After troubleshooting unsuccessfully, he opened today a ticket as the site was timing out at 60 seconds at each trial to access it. The site should not time-out but somehow display a clear error message. Apache can't run with disk 100.00% full. No hints here what the cause could be either. ;-)
3) The error log was truncated too in Virtualmin, and there was no warning either. But at least as last line was truncated and no new log entries were made, that gave me a hint that it could be a disk space issue....
4) Additionally, the "Quotas" panel didn't open to show the quota exceeded when looking at Virtualmin's panel homepage... You said in another ticket "good idea" it could auto-open, but I think it was for bandwidth quotas, not sure now...
5) BUG: When I opened it, there was NO red and the graph didn't work. It was displaying just something like "50000% used 500MB of 1024KB" (which I overread 500 out of 1024 means OK, specially that the graph was showing 0% usage (was all grey). Suggesting to fix graph to show ALL RED on any overuse, and text in red too. Additionally in all "xxx MB of yyy GB", never use a bigger unit on left than on right: e.g. "6 MB of 2 GB" can be ok, but "500 MB of 1024 KB" should display "500 MB of 1 MB" and that IN RED.
6) looking at reseller quota, all was looking fine (respected, no warning or red signs, could be done there too).
7) finally when i opened to edit the site, the QUOTA accordion section was closed (could auto-open), and only when I opened it there was finally text in RED showing that quota was exceeded).
As you see, most importantly for the reseller, there was NO hint of his mistake and no visible warning for the quota exceeded.
But also for us as admins, many opportunity to show the problems have been missed.
8) BUG: Finally, the most annoying one is that the backup of the whole site hanged because of QUOTA exceeded of ONLY 1 site...
Once we fixed to 1 GB the morning backup finished 19 hours later....
(btw i still owe you a reply on the Mysql collations questions, not forgotten, but just crazy days hope to feedback next week).