I've been running a WordPress.org Web site since 2010 and I've had a couple times now where the databases have been corrupted and something had gone wrong with the site.
In March when I was out of town, I was locked out of WP completely. It wouldn't recognize my username and password. Luckily, I happened to be staying with a girlfriend and her husband works for an ISP, and he was able to do some stuff to get me back in. He said the database that had all the usernames and passwords got corrupted but he was able to fix it. During the time I couldn't get into WP, the site itself looked fine, I just couldn't update anything on the site. I guess the database that had the categories and tags for all the posts also got corrupted, because until he was able to fix the problem fully, there were times when I would log in and categories and tags for all the posts were missing. Thankfully, he was able to fix it in a couple days and all was fine.
This past week, I had different issues. I was working in WP and suddenly the site and WP was inaccessible, initially getting one of those "it's taking too long for this site to respond" errors. Then I got I thought it was a server issue, so I contacted my Web host. They told me no, they had discovered a couple databases had corrupted and they would fix them. It took a while with back and forth emails and they were able to fix it.
I asked if there was anything I could do to prevent this from happening again, and they said they could not see a specific culprit in the error logs so could not identify the source of the problem. They suggested a plugin could have corrupted the tables and the only way to test this would be to disable them and then re-enable them one by one. The problem I see with this is, what if I do exactly this but the corruption does not happen? Since it has been a good 9 months since the last corruption and I have not added any new plugins since then, I would think it's possible I might not see any effect at all.
I'm scared to touch anything really b/c it's working now and I don't want to break anything. Any advice on how to figure out the possible problem area without drastically affecting the site?