Recently, I ran in to a problem, where a document that is stored in a SharePoint site was published through social media, the document URL was something like this:
After publishing the document, an error appeared when trying to access the site saying "Server is too busy, try again later" (site was down).
I've been administrating the farm that hosts this SharePoint site for more than 2 years, I was never given such an error as the topology contains 6 web front ends with very high specifications in terms of CPU, RAM, and Disk Space.
I investigated almost everything on the server and servers' resources seem to be healthy (Disk Space, RAM, CPU, Services up and running)...etc.
Operation team said that they noticed a heavy traffic coming from outside the country and they blocked the IP that was causing the traffic to the site, also after restarting the servers one by one, everything was back to normal.
I'm wondering what the issue is, is it because the document was announced on Social Media and huge number of people tried to download the document through the announced URL ?! or was the site exposed to some kind of a DDoS attack ?
Your advice is appreciated.