Slow Moodle Performance with Upgrades to 2.1.1

Slow Moodle Performance with Upgrades to 2.1.1

by Tadge O'Brien -
Number of replies: 9

Okay so I have been working with our technician on this for the last month and a half and I am running out of ideas. We moved from Moodle 1.9 to 2.1 and are currently running 2.1.1+ (Build: 20110928). We have about 4000 students total, and have seen slow times for example just pulling up the notifications to see the version information can take about 20 seconds as the admin.

I know that we are running the site on a VM that has 4 GB of Ram and a about 200 GB of space. It also looks like we are using a single processor@ 2.4 GHZ.

We believed that part of our problem was an email infinite loop due to our use of @noemail as an email domain for some students. To correct this we turned off most of the message notifications that would be sent to the student role via email and changed it to use messaging instead.

However after about a week with that off we are still having concerns regarding speed.

For example a teacher today was doing a lesson with about 20+ students and has been waiting for page loads. I know that in the past the page loads for a lesson activity like this would be between 3 and 10 seconds, now they have doubled or even tripled depending on the other uses of the server at this time.

Any insight would be greatly appreciated. If more information is needed please let me know.

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In reply to Tadge O'Brien

Re: Slow Moodle Performance with Upgrades to 2.1.1

by Chris Megahan -
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Tadge,

How many concurrent users do you need to support? What OS are you using? Does your PHP have memcache, APC or eAccelerator? Have you used monitoring to see what the processor, ram, disk i/o usage looks like? What is your query cache size in your MYSQL my.cnf file?

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In reply to Chris Megahan

Re: Slow Moodle Performance with Upgrades to 2.1.1

by Tadge O'Brien -

Chris,

We are using Ubuntu Linux 10.04, according to PHP Info we are using APC Support. We have process, ram, and disk io monitors. Our MYSQL query cache size is 36 M

We have seen due to the ram and process monitors,  that we are experiencing slow downs when we run the back up scripts we have set up. So it looks like this may be causing our issues. We have moved the times that the processes start and my next order of business is to start to look at backup best practices I guess.

One question I still have is how do we monitor concurrent users? I know that statistics in the past have also caused slow downs of the server so we haven't enable this, is there another way to find this out?

Thanks for the help, and if there is anything that seems out of place with our set up please let me know.

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In reply to Tadge O'Brien

Re: Slow Moodle Performance with Upgrades to 2.1.1

by Visvanath Ratnaweera -
Picture of Particularly helpful Moodlers Picture of Translators
Hi

> we are experiencing slow downs when we run the back up scripts we have set up

Is that the 124 GB monster backup you mentioned here http://moodle.org/mod/forum/discuss.php?d=186951#p820605 ? And the whole exercise runs "on a VM that has 4 GB of Ram [...] using a single processor@ 2.4 GHZ"?

That worked in Moodle 1.9? If you still have a backup of that VM, please upload it into a museum for great engineering achievements!
smile

Seriously, for those three man months you two have invested you could afford some impressive hardware - I mean real iron, not a VM in somebodys garden.

Apart from that I would check the sanity of those 124 GB in moodledata.
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In reply to Visvanath Ratnaweera

Re: Slow Moodle Performance with Upgrades to 2.1.1

by Tadge O'Brien -

Visvanath,

Actually it isn't a single course backup. It is our Moodle Data backup. So for the 100+ courses it is 124 GB.

We found that one of the main reasons that we were experiencing slow downs was that there was a snapshop within VM. Our tech didn't realize that a snapshot was actually a live VM link, so it was writting twice to the VMWare server. Though I think we are still running slow, just not as slow.

Thanks,
Tadge

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In reply to Tadge O'Brien

Re: Slow Moodle Performance with Upgrades to 2.1.1

by Brian Lockwood -

First port of call would be a php accelerator such as apc.

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Re: Slow Moodle Performance with Upgrades to 2.1.1

by Ken Task -
Picture of Particularly helpful Moodlers

In addition to what questions/suggestions have already been made, might check into apache config - how many httpd services does Apache initially launch and how many are in reserve to service new request?

When one runs cron it reports DB access times.  Of course, without some benchmark one only has observation to rely upon.

If on Linux server, there is a command line utility called 'ab' (apache bench) which will allow the simulation of number of concurrent request to the Moodle.  man ab will provide help in using the command.

There is something similar for MySQL.

What does http://yourserver/admin/health.php show?

'spirit of sharing', Ken

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In reply to Ken Task

Re: Slow Moodle Performance with Upgrades to 2.1.1

by Tadge O'Brien -

Ken,

Didin't know that there was the health.php link. Checked this and it says that the health is fine. So the applications must be okay, so perhaps we need to keep digging into what is outside of the app that could be causing this.

Thanks for the ideas.

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