Great, Ken. THANKS a lot for quick and detailed reply.
(And Sorry! for my previous PM I sent due to my lack of experience in this forums. I thought it was public). Also sorry for my English as non-native speaker.
Let me share my experience as I finally SOLVED the problem, and probably it can be similar maybe to other's arriving to this same forum after googling about the 'inodes'.
First I will tell my problem, then I will put in context
for other users who can be using also 'quizzes
' on their moodles and finally the (very) simple solution.
I'm not a developer. I'm a teacher at Uni and I just use Moodle for my work, so I decided it was fun to create and run a home-made website.
Currently, after two years, this website hosts one single course with 1.400 users.
My problem was that suddenly I ran out of inodes in my hosting company ('Hostinger', by the way). I reached 101% of my 200.000 inodes permitted.
Never heard about those 'inodes' in my whole life. When you use Moodle at Uni you never think about all those other limits
Inodes seem to be the meta data every single file or folder needs to be hosted in your website. So, no matter how small they are, as long as they exist, they use one. So, for a website like mine (quite small, with no more than 900 MB used, so, less than I GB) with a Premium service plan I payed it seemed to be quite surprising.
So, where did all those inodes come from?
The answer is the structure and usage of my website, which is full of Quizzes (dozens of them, with 'randomly selected questions' from database) and 1.400 active users. This seems to create a lot of tiny 'cache' files every day. The reason is related to the kind of quizzes used, as they are created 'randomly' for every single user, the amount of information stored tend to grow very fast.
The solution seemed to be just clearing those caches, which is something I discover it's quite easy from inside the Moodle itself, but the problem is that when your inodes are full, you cannot even enter your website! (No PhP can run, so no access is allowed for any user, included administrators).
So I was out of my own website and couldn't enter as Admin. Just surf the directories using the File Manager...
So: what was the solution in my case?
I used File Manager to delete another folder (out of Moodle, just an unused folder with rubbish, it was a secondary moodle folder I installed once in the past but never used again). This folder was stored in the same hosting plan and that helped reducing my inodes below the 100% limit.
As long as you get below the limit, you can finally enter as Admin. And when you're in, go to:SITE ADMINISTRATION / DEVELOPMENT / PURGE ALL CACHES
something like this:https://www.MYWEBSITE.com/admin/purgecaches.php
And purge all of of them:
This drastically reduced the amount of inodes used to just 14% of my 200.000 limit.
Great! very happy...
About the obvious conclusion ("...always purge the caches of your Moodle site before reaching the 100% limit of your storage plan...') A second conclusion I got about this is as follows:
Always keep also folder (unused) with rubbish or files you don't need –In my case, that secondary and unused Moodle site– which you can delete in order to create extra space in case of an Emergency.
I know other hosting companies do alert their customers when inodes limit is about to be reached (at 90 or 95%) but that was not my case. So that's why I think having the secondary and unused moodle can be a simple lifeguard!
Thanks to all users in the forum. Your help is very valuable!