Mysqlnd ms drupal hosting
Posted by shinguz on March 20, 2012 at 9:12am
We are looking for web-sites which are running on the highly available Galera Cluster for MySQL.
We know that some installations are out there because there are some Drupal specific configuration parameters in Galera Cluster. But we do not know who it is.
So if your run Drupal on Galera or if you know who is running Drupal on Galera please let mee know.
Oli (oli dot sennhauser at fromdual dot com)
Posted by pdrake on August 23, 2012 at 1:11pm
We have investigated Galera Cluster as a possible high availability solution and I would also be interested in hearing about experiences running Drupal on Galera.
Posted by zebb on August 24, 2012 at 6:50am
If your Drupal servers connect to one Galera node, the system should work fine out of the box. In this use case Drupal uses Galera Cluster in master-slave model, and you need to figure out how to implement master fail over.
More interesting use case is multi-master, where each Drupal server can connect to any Galera node at will. In this model, you may face issues with Drupal caching. But, by using memcached for caching you should be fine.
Also, some drupal modules may be picky about write success. If two drupal servers write to same database row at the same time in two separate Galera nodes, one of the transactions will get deadlock error code. Drupal should understand to retry deadlock errors, but this does not always happen. To workaround this, you may configure Galera to retry the deadlocked transaction on behalf of Drupal. Use wsrep_retry_autocommit in my.cnf to enforce this, e.g. wsrep_retry_autocommit=5, should be fine to use.
So, try along following guidelines:
=> use innodb tables
=> use memcached for caching
=> experiment with wsrep_retry_autocommit, if need be