Cluster shared storage

Cluster shared storage

autor Daniel Nor -
Počet odpovědí: 5
We are configuring a clustered Moodle setup with separate loadbalanced PHP and NGINX nodes. Running hardware database cluster to connect it.
The question comes down to the shared storage. NFS seems to be not reccomended, and it is very slow. What is the alternatives reccomended by Moodle?
Průměr hodnocení: -
V odpovědi na Daniel Nor

Re: Cluster shared storage

autor Howard Miller -
Obrázek: Core developers Obrázek: Documentation writers Obrázek: Particularly helpful Moodlers Obrázek: Peer reviewers Obrázek: Plugin developers
I'm not sure why you think NFS is not recommended. NFS is fine. However, don't rely on it for anything performance critical. This is likely to come down to the Moodle Cache. Implement a Redis server for that and you should be fine.
V odpovědi na Howard Miller

Re: Cluster shared storage

autor Daniel Nor -
Thank you for your feedback. What do you mean by "performance critical". If it is, what should you rely on? It will be used to hosting alot of clients and we are in need of a performant and redundant setup.
We experience alot of read and write when using NFS, slowing everything down. Does this come down to Moodle Caching?
V odpovědi na Daniel Nor

Re: Cluster shared storage

autor Howard Miller -
Obrázek: Core developers Obrázek: Documentation writers Obrázek: Particularly helpful Moodlers Obrázek: Peer reviewers Obrázek: Plugin developers
Sorry if I wasn't clearer. Moodle relies heavily on caching. By default, it will use files in wherever your 'moodledata' resides. If this is NFS then, yes, your site will probably be very slow. For anything beyond a trivial site you should implement a "proper" cache. There are alternatives but Redis is well-used and does a good job.

Once you have that in place, NFS should be absolutely fine. Even for very large sites. 
V odpovědi na Daniel Nor

Re: Cluster shared storage

autor Visvanath Ratnaweera -
Obrázek: Particularly helpful Moodlers Obrázek: Translators
The point is Moodle reads and writes to many places. Some are critical for scalability others not. For example moodledata/filedir is not critical. All sorts of caches are. So to get the maximum from the hardware you need to distribute those places accordingly.

That was about performance. Redundancy is a different topic, a harder one IMO.

V odpovědi na Daniel Nor

Re: Cluster shared storage

autor Visvanath Ratnaweera -
Obrázek: Particularly helpful Moodlers Obrázek: Translators
More documentation can be found in the Hardware and performance forum https://moodle.org/mod/forum/view.php?id=596, for example Server cluster. Make use of the Advanced forum search on this site https://moodle.org/mod/forum/search.php?id=5.

P.S. This used to be a topic in the Hardware and performance forum. It was reported there that a new group, a Matrix group(?), is now in charge.