Posted by Riley 4 Prez on June 18, 2012 at 7:47pm
I work for a company that installed drupal about a year ago.
We provide content management services for a particular market niche.
We're currently doing OK mysql wise with a master feeding a slave backup server. However, we're growing pretty quickly and we may need a higher performance architecture in a year or so.
We're also very keen for the system to be very robust, and the time required for failover to the backup db server gives us some heartburn.
Sooo.....
As the subject asks, is anyone actually using mysql in master-master mode for robustness and scalability? Is drupal7 multi-master safe?
I'm not looking for someone to solve my problems, just wondering if anyone has solved their issues with master-master.
Thanks!
Comments
Short answer, nope. We do
Short answer, nope.
We do have a client that has multiple masters, but writes are still directed only at one of them - the multimaster setup is just for redundancy so that they can fail over quickly if required.
What are some of the problems
What are some of the problems with a multi-master setup? Is it worse for D6/Pressflow6?
Writes directed to one server?
I thought I'd read of quite a few problems with writes going to a master and reads coming from slaves. The root of the problem seems to be that drupal modules will write something, then immediately turn around to read it for page display. That doesn't work if there's a variable many-millisecond delay getting writes to slave(s).
Mark, how does your client deal with that? If D7 is read-slave-safe it's news to me.
AFAIK D7 is read-slave-safe,
AFAIK D7 is read-slave-safe, but to avoid those types of issues you can be selective with which queries get sent to the slave. Most Views/EFQ/Search/other-complicated-queries should be slave-safe. However I've never had to go this far. Varnish + Memcache + Solr + DB-tuning + query-tuning + block-caching + views-caching has always provided more than enough performance improvement in the DB. I find that the remaining bottlenecks are almost always on the PHP side.
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Dave Hansen-Lange
Director of Technical Strategy, Advomatic.com
Pronouns: he/him/his
I have clients running
I have clients running multiple master databases all with write capability using the MySQL Galera plugin.
Toonix.com probably puts the biggest load on the db as there is no page level caching possible in the game and has a db cluster accepting requests from the web servers.
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Full Fat Things ( http://fullfatthings.com ), my Drupal consultancy that makes sites fast.