Moodle in English: Mirroring moodle between two servers

Mirroring moodle between two servers

by Phil Hopfner - Wednesday, May 7, 2008, 11:54 AM

I'm pretty new to Moodle and I'm looking at setting up two systems that are redundant to each other. I think I've got MySQL multi-master replication working just fine, but could use a couple of pointers on what data exactly to replicate between two Moodle systems.

I see references to using rsync (or unison) to mirror the moodle_data directory - but does it cause problems to simply rsync both ways between two servers? Are there sub-folders I need to exclude form the rsync? Do I need to bother to rsync the moodle_web folders as well? And what sub-folders/files should I exclude from there?

Any thoughts/hints greatly appreciated. Thanks!!!

Re: Mirroring moodle between two servers

by Visvanath Ratnaweera - Wednesday, May 7, 2008, 4:00 PM

This topic came up a couple of time, see eg. http://moodle.org/mod/forum/discuss.php?d=62917

My guess is, this won't be easy due to the dynamic nature of Moodle.

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Re: Mirroring moodle between two servers

by Phil Hopfner - Wednesday, May 7, 2008, 11:16 PM

Thanks - I hadn'tcome across that discussion yet!

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Re: Mirroring moodle between two servers

by Taylor Judd - Wednesday, May 7, 2008, 10:12 PM

Hi Phil,

I believe Master-Master Replication could work in Moodle but it would be tricky. If you really want to do Master-Master setup I would suggest looking at mysql 5.1 and using row level replication which should help with the auto-incrementing and other evaluated queries transferring identical results. It would be an easier setup for you, and you'd get just as good performance unless under extremely high load, to do a load balanced application setup.

Get a load balancer hardwarer or software(squid, perlbal). Put that in front of 2+ application servers. Have each application server connect to the same NAS/SAN for the moodle data directory. Then create a strong database server for each of the application servers to connect to.

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Re: Mirroring moodle between two servers

by Phil Hopfner - Wednesday, May 7, 2008, 11:15 PM

Thanks for the reply...but I am running MySQL 5.1 and I do have Master-Master replication already working. I can see changes mirrored between the two systems (as far as the MySQL db is concerned).

I'm just looking to see if anyone has an answer re: mirroring the trying moodle_data folders. Do I mirror the entire folder or just certain subfolders. Same for the moodle_web folder/subfolders.

I could NFS mount the moodle_data folder as a shared filesystem....but that's not why I am trying to see if I can accomplish ( a fully redundant live setup).

Thanks for the reply!

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Re: Mirroring moodle between two servers

by Jonathan Moore - Thursday, May 8, 2008, 12:00 AM

Phil,

You should look into using drbd for the syncing of the files. We actually use this instead of the mysql based replication services. There are ups and downs to this approach but it provides a bit simpler setup for us.

Failover can be controlled with another program called heartbeat.

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Mirroring moodle between two servers