thanks much - professor James
I have this palm sized computer for taking into class when I am teaching. It is called Odroid U3. It has a primary memory called eMMC of 64Gb, and another 64 Gb on a SD card. I will install all the apt-get on eMMC. How do I configure Moodle to store all the course related files on the SD card? I am guessing all the database related files should be on the eMMC because it is much faster. Does the course related storage all go into the database or will it be possible to put text, graphics, and videos etc. on the SD card somehow?
You can configure (in Moodle's config.php) the $CFG->dataroot to be where uploaded files go. Everything else is in the database. You also need to make sure you you set another config parameter, $CFG->cachedir, to point to fast storage or your site will be very slow.
You may want to Google 'Moodle on a USB stick'. I've never done it, but it strikes me that a lot of your issues will be similar.
If you run Disk Usage Analyzer, you will probably see that everything is taking a lot less space than you think, unless you have a bunch of videos included. If you are not using a lot of videos, then I would recommend putting everything on the eMMC because it is so much faster than the SD card. I have an Odroid XU4 and that's the way I have it set up.