We have setup Moodle 2.6.1 with the following infrastructure:
Server setup
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1) 5 web servers running PHP 5.6 and OPCACHE
2) 1 Mysql 5.6 database server
3) 1 hardware load balancer
4) 1 memcached server using the memcached api for MUC
MUC setup
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1) memcahced API is used
2) 1 memcached server for MUC
3) Almost all known cache definitions are using memcached except:
a) Event invalidation - Default file store for application caches
b) Calendar subscriptions - Default file store for application caches
c) Course categories lists for particular user - Default file store for application caches
d) Course categories records - Default static store for request caches
e) Repositories instances data - Default static store for request caches
f) Data used to persist user selections throughout Moodle - Default session store for session caches
g) Folder name cache - Default session store for session caches
h) Helper caching - Default static store for request caches
4) No change is made to default stores
a) Default file store for application caches - File cache
b) Default static store for request caches - Static request cache
c) Default session store for session caches - Session cache
We have performed a load test (5 testing courses with 300 users for each one) on this platform doing the following activities repeatedly by each user in an hour:
1) Login
2) Read news forum
3) Submit an assignment
4) Perform a quiz with 10 questions
5) Reply to a discussion topic
6) Read a page
7) Read a folder
8) Logout
The result is very good. We find that the quiz performance of Moodle 2.6.1 is better than the previous version 2.4.4.
The average response time is <= 1.6s with very small number of errors. In general, the action of
replying the forum has recorded the maximum response time of about 60s.
However, the followings are some interesting observations:
1) Moodle 2.6.1 uses more cpu resources by about 30% than the previous Moodle 2.4.4 version
2) Using a single memcached server for MUC is better than using 2 or more memcached servers
3) Submitting the quizzes is in general faster than replying the forums
4) A lot of Moodle errors would occur if we change to use memcached session instead of database session in config.php in an attempt to achieve even better performance
May i have your valuable comments on these 4 observations? e.g. how to configure the MUC? number of memcached servers that should be used? how to further tune up the Moodle server?
Thank you very much.