We are running separted web servers and data base server and this is what we got with 260 users on at once. Most doing quizzes. How do we do better?
Is there something obvious in this data apart from the "It is too slow to use" obvious.
We are using verreion 2.2
But, then 260 users taking a quiz at once is not an everyday affair either ;)
If it is, without knowing anything about those two servers (and the network infrastructure), how can one say they should do better?
Did you go through the initial information in the introduction to this (Hardware and Performance) forum?
I think the root cause there is the DB reads = 443. That is way too high.
The load average is also crazy. That is the number of processes your server is trying to run simultaneously, and so should stay less than the number of processors cores in your server. I am pretty sure that you server does not have 84 cores, so that means it is massively overloaded.
The jury's out on the load average though - it could just be high because there are 80+ other threads stuck waiting for the database server to respond, or there could be massive file system contention causing this (e.g. write locks). I've legitimately seen load averages of around about 20-50 on a Sparc system with 24-32 cores, and we used to have systems with 64 cores (albeit rubbish slow sparc cores). I've also seen file system issues cause this when an NFS file server got it's knickers in a twist. Load average is the number of items in the queue waiting to be processed rather than the number of items currently being processed.
Either way, we need much more information to determine the true cause...
Here is another one from slightly earlier yesterday. This was the time taken to refresh the site homepage in Chrome.
Are we thinking we need to do work on the DB server or the web server?
Today with 58 users on and no-one doing quizzes it is just humming along OK.
As already pointed out by others, load averages of 67, 83 are abnormal. The 0.71 is ok, it should generally remain under 1. You technical staff need to come up with an explanation!
Apart from that, you haven't provided a single peace of information requested in the intro to this forum, I quote:
"Please include as much background information as possible about your hardware, the operating system, the web server, the database server, the PHP scripting framework, etc. If your machine is virtualized, also mention the host hardware, the operating system, the virtualization technology used and the resources assigned to the guest OS. If you use a hosting service, mention either the hosting provider and the package or the resources they've allocated to your Moodle instance."
Also the documentation on http://docs.moodle.org/en/Performance (mentioned in the same intro as above) is compulsory before discussing performance of Moodle.
The 'advanced search facility' (linked in the same intro) is also handy in finding similar discussions in moodle.org.
The shots above are when logged in as an admin.
Today with 60 to 70 users online.
Admin looks like this.
Student login like this.
I will provide Sever Specs when my techie tells me what they are. Sorry Vishvanath. I will get better at this.
Both the Database and web server are hosted on a HP DL380G6 with a HP P2000 SAN using Vmware ESX.
- 8GB Memory allocated
- PHP Version 5.3.3-1
- 1 vCPU allocated
- Moodle 2.2.3
- 8GB Memory allocated
- 2 vCPU allocated
- MySQL 5.0.51a
If you require any other specs please let me know
we are using the overlay theme, tried switching to the standard theme and it make no difference. We also tried removing items from the front page such as upcoming events, calendar but this only made a small difference
to add the data to the bottom of the page enable performance info under Development > Debugging > performance info
Looking at our server specs above, do think we have enough "hardware grunt" to run quizzes with 200 users at once. This is what is required.
We also experienced a slow down in running about 120 users simultaneously on multiple quizzes. We didn't have the stats switched on so couldn't tell too much except that page load times became unusable.
We are using some of Tim's OU question types (like drag and drop).
We have a single server (32 bit so 4 Gigs) for both database and moodle - so we will look at fixing that up during our winter break. We will also take that opportunity to upgrade to 2.3.
What we did see were database errors in the logs coming from processattempt.php
"Database transaction aborted automatically" processattempt.php
I would be interested to hear of any future issues and solutions if you have them.