Moodle Performance and

Scalability Assurance

Jonathan Moore

Analysing Usage

●We size for the highest peak

●Describe the peak scenario

●How many users?

●How short of interval?

●What are they doing?

●How much growth is expected?

The mdl_log

●A wealth of information

●Many sites have > year of data

●Determine concurrency

●Determine % of activity types

●Visualize historical usage

Optimizing Performance

●Use a PHP accelerator

●Balance your memory budget

●Make InnoDB buffer pool same size as DB (see

mysqltuner.pl)

●Most sensitive to slow disks

–Sessions

–Moodle source

–Moodle database

Some General Sizing Guidelines

●~25-30 MB per apache client /w accelerator

●~200-250 logged in users per core

●~4-6 x more resources for a user's first minute

●~10 logged in users supportable per apache child

●DB generally 1/10 size of Moodledata folder

●5-10% of population is common peak for

concurrency

JMeter Benchmarking

●Simulates simultaneous user activity

●Gathers response and throughput results

●Not a browser can't test javascript

●Can use to measure +/- of changes

●Can use to estimate expected concurrency, but

harder

What to Use for Testing?

●Copy of production for test site

–+Harder for server to cache

–-More likely errors in results due to broken content

–-Have to reset user passwords

●Synthetic test site

–+Can use known good content less false errors

–-Takes a lot of time and effort to prepare

–-Smaller DB = easier server caching

●Hybrids

Testing Changes

–Single test user and course may work well

–More accurate the test rig less likely to miss problem

–Run same test between changes

–If results degrade don't move forward with change without careful review

Measuring Concurrent Capacity

●Test users, enrolment, and course population

should be on par with production site

●Test set mix should reflect activity % of production

site

●Calculate

–Simultaneous logged in user count

–Simultaneous logging in users count

–They are different

–Know what you need for each

Moodle 2.6 and JMeter

●New integration available

●Creates test plan with many activity types

●Provides comparison reports

●Only single user / single course test?

Tools

●jMeter

●SQL queries + mdl_log

●PHP Accelerator

●Cacti, munin, nagios, etc

●CLI: top, sar, innotop, mysqltuner.pl etc

Questions?

●jonathan@elearningconsultancy.com

●Twitter: @moorejon

●Skype: moorejon07