Now to the point. We are investigating different options to run Oxwall with high-availability and horizontal scaling in mind.

With static content offloaded to CDN and user files to cloud storage (with CDN distribution) - there is still issues of HA and ability for horizontal scaling.

We have tested nginx with sticky sessions. This gives us ability to add/manage/remove dynamically web servers.

GlusterFS allows secure (for geo case) replication of Oxwall file system.

Now it is turn for scaling out DB.

We have considered Galera with MySQL -> the problem here - it supports InnoDB but not MyISAM. Conversion of MyISAM tables brings problems with dead locks. So ideally a solution should be without changing storage engine. Percona and alike are based on Galera - same problem.

We are contemplating to test MySQL Cluster solution and MySQL native replication mechanism (with master-master setup). In case of native replication - nginx has option to configure upstream and downstream (to write only to one DB, but to read from any).

By the way, on the way we found usage of "INSERT DELAYED". In MySQL 5.6 and above -> it is deprecated to not supported.

If you have solved DB cluster problem or any of the above - we would appreciate it if you can share your experience.

Thank you.

Kind regards,

TY