It takes more than 5 seconds for the direct link to be generated. Both uploads and downloads are also slow, and I strongly believe that my network bandwidth is not exceeded yet. What's the problem and what should I do?
First of all you have to install atop ('yum install atop') and run it for as least 10 seconds. If you're getting some red-colored values near the disk names then you're experiencing a high disk IO load (Note: do not confuse with occupied disk space).
The possible solutions are:
- Moving some of your popular files in another place
- Making free user speeds even slower so that the premium ones could get a priority
- Asking your hoster what's he can do (will need to measure the disk reading speed in a peek time and ask how you can boost it by two)
- Applying for SSD caching (only makes a sense for video sites which have a small number of really hot files
- Webseeding the popular files with BitTorrent
Update: you also have an alternative of making the hot files seeding with BitTorrent rather than being sent through HTTP since 2.3.
In order to do that you'll have to setup the Torrent mod on the server where you're experiencing a high disk IO load, and put the hot file criteria for the different types of users in admin_settings -> Users Limits. The download flow will be looking pretty much the same as the regular one, with an exception to that the user will now get a .torrent file instead of the file itself for all files that are considered as hot on that server.