General performance question

General performance question

by Heinz Felfe -
Number of replies: 15

Hi there,


for our internal team we are running Moodle instances on a Linux - server (Ubuntu 16.04).


Since a month or so more user use the Moodle instances.

We also installed another Moodle - instance which for a Moodle update

process. This instance is not so much in use at the very moment.

Moreover I installed different versions of the Moodle Db.


As a result the performance goes down.

I think I have to dig through the performance recommendation ...

... but do you have a guess where to start in order to find the bottleneck


DB

PHP

DISK


What are the  "normal suspects" ?


Thank you!


Best,


Heinz


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In reply to Heinz Felfe

Re: General performance question

by Howard Miller -
Picture of Core developers Picture of Documentation writers Picture of Particularly helpful Moodlers Picture of Peer reviewers Picture of Plugin developers
You're right - you'll need to dig through the performance recommendations.

Also consider your cache (MUC) configuration. A classic mistake is to have file caching on an NFS share. This doesn't work.

Other than that... are you doing anything to monitor performance? It's worthwhile installing munin (very straightforward on Ubuntu) to monitor the server. This should spot any resource bottlenecks.
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In reply to Howard Miller

Re: Aw: Re: General performance question

by Heinz Felfe -
Hi Howard,

thanks for your fast reply ... !
It is absolute clear that one has the recommendations ...
I have munin installed for years. it is never showing probs (critical, warning unknown).
We don't use nfs - mounts. However additional device are mounted locally on the server.

I attached a munin graphic concerned with I/O of that device. It displays some peaks but that is
not very telling, is it ?

Can you tell may be the relevant munin figures ?

OK so I think this a bit un precisely ... excuse me. I only got the feeling that the Moodle gets slower
and slower due to more active users, more installed databases etc
... so the question is rather how to serve the grown demand. 

So I'd like to distinguish between 

- munin monitoring  (load, I/O etc)
- db (MariaDB)  What performance tool do you use   
- PHP (PHP7)  - caches
- Apache config

Is this list exhaustive ? 

Thanks for you input.

Best,
Heinz












 

 












Attachment Bildschirmfoto 2019-06-06 um 11.31.32.png
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In reply to Heinz Felfe

Re: Re: Aw: Re: General performance question

by Howard Miller -
Picture of Core developers Picture of Documentation writers Picture of Particularly helpful Moodlers Picture of Peer reviewers Picture of Plugin developers
I only ask because we often see "my server is slow!" and the response to "well, what have you done about it?" is silence wink

At least you have eliminated basic issues such as running out of memory or similar resources.

Have you done anything about tuning Apache and MariaDB? By default, Ubuntu tends to allow Apache to consume too much memory (it is optimised for serving static pages) and for MariaDB not to use enough (it is optimised for small databases). For a production site you need to allocate memory to these services and tune them appropriately. There are lots of online resources (and tools) for this.
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In reply to Howard Miller

Re: Re: Re: Aw: Re: General performance question

by Emma Richardson -
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Is it just me or does everyone get huge smiley faces in the email version of these posts?smiley

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In reply to Emma Richardson

Re: Re: Re: Re: Aw: Re: General performance question

by Howard Miller -
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I switched off emails from this site years ago....
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In reply to Emma Richardson

Re: Re: Re: Re: Aw: Re: General performance question

by Rick Jerz -
Picture of Particularly helpful Moodlers Picture of Testers
This is MDL-64598.

Yes Emma, I get these too. I hope this problem is fixed soon.
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In reply to Rick Jerz

Re: Re: Re: Re: Aw: Re: General performance question

by Emma Richardson -
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Thanks Rick!  Glad it is not my email client!

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In reply to Emma Richardson

Re: Re: Re: Re: Re: Aw: Re: General performance question

by AL Rachels -
Picture of Core developers Picture of Particularly helpful Moodlers Picture of Plugin developers Picture of Testers
I believe the problem started in 3.6 when Moodle seems to have started serving up the svg versions instead of the png versions of the various files in the yourmoodle/pix folder. I had to add width and height styles for some of them that I use in two plugins I maintain.
Average of ratings: Useful (1)
In reply to AL Rachels

Re: Re: Re: Re: Re: Re: Aw: Re: General performance question

by Rick Jerz -
Picture of Particularly helpful Moodlers Picture of Testers
The puzzle is that the problem does not always occur (for me.) For example, Visvanath's post shows the emoji just fine in its email to me.

I have tried to track down what the exact problem is by looking at the html view of emails, and I remain puzzled.
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In reply to Rick Jerz

Smiles uncontrolled?

by Visvanath Ratnaweera -
Picture of Particularly helpful Moodlers Picture of Translators
The cause, according to Howard, is here https://moodle.org/mod/forum/discuss.php?d=381111#p1536527. If you ask me, it is just one of the evils of HTML mail.

Ladies and Gentlemen
a) Why do you call this discussion "Re: Re: Re: Re: Re: Re: Aw: Re: General performance question"?

b) Isn't this sub-thread better served in the Moodle community sites forum?
sad
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In reply to Visvanath Ratnaweera

Re: Smiles uncontrolled?

by Rick Jerz -
Picture of Particularly helpful Moodlers Picture of Testers
Maybe so.  But here are a couple of things.

1) Howard may be on to something, but MDL-64598 is still open, and the problem is intermittent, which makes it more troublesome.
2) The Re: Re: Re is MDLSITE-5811, maybe soon to be fixed.  (I find it interesting that today I am getting some emails without any subject.  Hmmm.)
3) Yes, we are off topic. The emoji problem is sometimes hard to duplicate, so when one sees it, as Emma did, it might be best to ask if anyone else sees the problem. We have had some forum discussions about it, but the problem continues.
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In reply to Howard Miller

Re: Re: General performance question

by Luis de Vasconcelos -
> A classic mistake is to have file caching on an NFS share. This doesn't work.

What if you are using SSD storage for the NFS share? Is that also not recommended?
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In reply to Luis de Vasconcelos

Re: Re: Re: General performance question

by Howard Miller -
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The issue is not so much the technology - it's the speed. NFS is, for the most part, very slow.

The speed tests in the MUC configuration are your friends here. 

However, if in doubt set up a proper cache (e.g. Redis)
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