Hardware and performance

 
 
Picture of Gary Lebowitz
Terrible performance with GoDaddy VDS - Help!
 

Hello all, over the past few days I have had enormous problems with a GoDaddy VDS due to another user's "overtaxing resources". When I do a "top" via SSH and look at average load it sometimes goes from like .01 to 2.5 in a matter of a few minutes due to a rogue process initiated by that user. I have tried to have the user be notified and tech support have opened a ticket as they call it and they have gone the extra mile and killed the process, but this is becoming a mess since I have a live course running that's pretty high profile and with people trying and often failing to log in from around the world (and getting Apache 500 error at regular intervals). Could someone tell me or point me to a spec sheet that tells me exactly how much RAM and what sort of processor I need for a single course using Moodle 2.3.2 and having 30 students. Right now I have 2 GBytes dedicated to my applications, but I am sharing the processor. Bad. If I go to one of the dedicated server plans that would mean the entire processor would be for me. But I am not sure if I should go to a iE3 with 2GBytes or iE5 processor with 4GBytes. Any expert help here would be most appreciated. For the moment I must reboot regularly to keep the party going. sad

 

 
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Picture of Visvanath Ratnaweera
Re: Terrible performance with GoDaddy VDS - Help!
Group Particularly helpful Moodlers
Hi Gary

Does the post https://moodle.org/mod/forum/discuss.php?d=221933 succeed the previous post? Ist is OK if we declare https://moodle.org/mod/forum/discuss.php?d=221933 as the follow-up?

Have you abandoned the other thread "Problem with Godaddy Virtual Dedicated Server nd Moodle 2.3.3" https://moodle.org/mod/forum/discuss.php?d=221307 ?
 
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Picture of Gary Lebowitz
Re: Terrible performance with GoDaddy VDS - Help!
 

Hello Visvanath, actually it's the same problem. But, yes, I suppose the other can be considered to have been abandoned. I now am looking much more closely at this issue on my virtual dedicated server via SSH and I see it has something to do with PHP-CGI and the mysqld daemon, which drive the average load up; normally not over the top, but sometimes over the top, something reflected in the numbers I mentioned in my posting. Perhaps there is a better place to post this information so that people who've "been there" can give their views on it....

 
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Picture of Rick Jerz
Re: Terrible performance with GoDaddy VDS - Help!
Group Particularly helpful Moodlers

Gary, I still wonder if it has something to do with your overall setup and Plesk.  On Sunday, I know that I had at least 20-30 students in my Moodle (GoDaddy VPS), some concurrently taking a two-hour long exam, many making posts, and I did not have any problem nor did I see any substantial load on the server.  In fact, since I was seeing a lot of students, I actually ran TOP and really did not observer any substantial loads.

Our of curiosity, what are your 32 students doing most of the time?  Taking quizzes?  Posting discussions?

 
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Picture of Simon Story
Re: Terrible performance with GoDaddy VDS - Help!
 

Hi Gary,

Running PHP as a CGI is a very inneficient method. This means for every request to the webserver has to start a PHP interpreter, interpret (Read, compile) Moodle, run database queries against MySQL and then generate the output. The output being the webpage you see.

There are more efficient methods that mean that the PHP interpreter (I wildly paraphrase here) is already running, and Moodle exists in memory in an already compiled state and MySQL is already somewhat ready to receive queries.

How did you install Moodle? What distribution of Linux is this machine running?

 
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Picture of Gary Lebowitz
Re: Terrible performance with GoDaddy VDS - Help!
 

Hi Simon, very kind to get back to me with this. I see that I get the spikes when I do a "top" via SSH whenever users log in and I see PHP-CLI command called followed by mysqld. So this is a semi- pinpoint of the issue. I am using Moodle 2.3.2 and I installed it, or tried to, using the one-click install feature in Moodle. But that idiot-proof way of installing didn't work, since it wanted to put Moodle into the /httpd directory while I had a domain I attached in what was automatically named /site1 by Plesk when I attached the domain to my dedicated IP address. So maybe I confused the thing. In any case I am ready to listen to any fixes or suggestions; I could also use GoToMeeting to actually show you or others what I'm seeing when doing a "top" in real time. Whatever. Or send /var/log/https error_log info. For the moment I have cut away all the fat I can imagine in other areas. Set crond to a nice level of +19, etc. But whenever there are multiple logins or even single sometimes there are dangerous spikes in average load. I will be watching your response. Gary  

 
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