JATOS on DigitalOcean : problem reaching JATOS homepage / single experiment
Hello everyone,
we are using a 2GB, 50GB SSD DigitalOcean droplet (docker-ubuntu-s-1vcpu-2gb-fra1-01) to launch JATOS studies for a few months so far. Everything was running smoothly until the last two days when experiment links started to load really slow (1-2 minutes) and sometimes the link couldn't be reached at all. I also have problems reaching our JATOS server homepage. We are currently having about 20 uploaded studies, with approximately 60-200 participants in the databases, and General Multiple Worker running on all studies.
I am wondering is it too much for the memory of the droplet we had chosen? We had even more uploaded studies (around 30), and their datasets were almost empty. Deleting those studies didn't help much with this problem, and I'm not sure whether I should delete collected data (ofc after backup :D) in order to run studies smoothly again? The other option is resizing the droplet, but I'm not sure if conducting that action going to delete all the studies and data collected.
I also tried to analyse the usage graphs on my droplet: current usage differs from the days before only on disc IO activity. Read usage was lower in the days before and now is similar to write usage (around 15 mb/s). I'm not sure whether this indicates that more deleting should be done?
I would really appreciate some help with this issue, I hope that there is some simple solution which I cannot see due to lack of knowledge about servers. :)
Thank you very much everyone in advance!
Kindest regards,
Uroš
Comments
Just to let you guys know that the solution was very simple. I only needed to restart my DigitalOcean droplet, by turning it off and on again. After that, all the data was saved, and everything remained as it was. :)
Hi Uros,
Somehow your question slipped my attention. Good that you found an solution already.
But I want to answer some of your questions anyway. Your problem sounds like you were running low on resources, probably memory, on your JATOS server - as you already have guessed. 2GB is usually enough for a small to medium size JATOS but it always depends on how much your studies put load on the server. Can you remember from the monitoring of your server, how much the maximum memory was?
delete collected data
Result data is stored in the file system (even the database is). Deleting collected data only helps if you are low in disk space - not if you are low in memory.
The other option is resizing the droplet, but I'm not sure if conducting that action going to delete all the studies and data collected.
That's an option. And no, it does not delete any collected data. All result data are safely stored in the database or file system and they will still be there after a reboot.
Another possibility might be, if you are running other programs on your machine, e.g. a database, to limit the memory that JATOS can use with the -Xmx parameter. E.g. to limit it to 1GB you'd start JATOS with:
Hope this helps! Best,
Kristian