Moodle in English: Slow moodle 2.7 on update

Slow moodle 2.7 on update

by Nathan Friend - Monday, September 1, 2014, 3:46 PM

Hi,

We're recently updated our Moodle site to 2.7.1+ and switched to the Elegance theme. When updating e.g Editing the HTML in a category I get a 2 minute delay. No errors, works but just takes it's time.

Set up is 1 NFS/Database server and 4 load balanced web servers using the NFS for webroot. Sessions directory is symlinked to the local disk of each server to prevent file lock issue.

Servers are running OpenSuse 13.1, MySql 5.5.38, PHP 5.4.20

Attached network requests screen grab.

Any suggestions on where to look next?

Network requests

Cheers,

Nathan.

Re: Slow moodle 2.7 on update

by Howard Miller - Monday, September 1, 2014, 4:41 PM

If your 'moodledata' is all on NFS and you haven't touched your MUC settings then, yes, it will be slow.

You need to set up a cache server (e.g. memcached) and point your MUC (cache) settings at the new cache server. Then, I am reasonably confident, all will be well.

I'm going to guess that you upgrade from a version <2.4?

See - https://docs.moodle.org/27/en/Caching

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Re: Slow moodle 2.7 on update

by Nathan Friend - Monday, September 1, 2014, 7:57 PM

Ah OK a thanks, will setup caching. Perviously running 2.2.

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Re: Slow moodle 2.7 on update

by Howard Miller - Monday, September 1, 2014, 8:03 PM

That settles it then. The new MUC was added in 2.4 and stuffed anybody who was using NFS

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Re: Slow moodle 2.7 on update

by Nathan Friend - Tuesday, September 2, 2014, 5:37 PM

Yes, and I should have read up on MUC before the upgrade. Don't remember seeing any notes about this in the upgrade documentation.

1) I've setup a memcached server.

2) Installed the php extension on the web servers

3) Added a memcached instance to moodle

4) Mapped Application under stores used when no mapping is present to memcached server

5) Created a localcache directory on the web servers and add $CFG->localcachedir = '/localcache'; to config.php

It's taken the time down from 2.2 mins to 12.2 seconds. Useable now, but still more work to do. Will start the profiling in the half term.

Cheers,

Nathan.

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Re: Slow moodle 2.7 on update

by Howard Miller - Tuesday, September 2, 2014, 5:53 PM

It did cross my mind that 2.2 mins was a lot more than i had seen before so it would appear you have some other problem. It's also possible to cache your sessions in memcached (see config-dist.php) but you MUST use a different instance to MUC. That may help.

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Re: Slow moodle 2.7 on update

by Nathan Friend - Tuesday, September 2, 2014, 6:11 PM

OK that's an interesting idea, so could I use the same mcached server but run another process on a different port and create another instance in Moodle. I guess you have to keep it separate to prevent a cache purge deleting the sessions.

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Re: Slow moodle 2.7 on update

by Howard Miller - Wednesday, September 3, 2014, 6:33 PM

Exactly that, yes.

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Hardware and performance

Slow moodle 2.7 on update