[opencms-dev] Can different installations of OpenCms connect to the same db schema?

[Achim Westermann]

Hi Edwin,

thanks for sharing your way to set up a cluster.

> I think most of you would agree that OCEE is worth to pay for the multiple
> OpenCms scenario. But it meant that you also have to pay for more money on
> DB cluster.

No that is not required. You can use mysql replication as you describe with ocee cluster. So OCEE Cluster is an alternative to the solution 
you describe:


> Most of the client using OpenCms is for "Free of Charge" and minimizing the
> cost on frontend. So OCEE is meaningless for them.
> 
> In my past project, client wants to have load balancing on the website. So,
> we had 2 MySQL for serving 2 OpenCms instance in 2 machine. Let see my setup
> below.
> 1. One OpenCms and One MySQL is both on the one machine.
> 2. We defined the 2 machines as Master machine and Slave machine.
> 3. Let say OpenCms and MySQL in Master machine be m_OpenCms and m_MySQL. In
> Slave machine, that is s_OpenCms and s_MySQL.
> 4. We set up an one-way replication (it's free!!!) between m_MySQL and
> s_MySQL. The replication direction is "m_MySQL -> s_MySQL".
> 5. m_OpenCms is for authoring and displaying content. s_OpenCms is only for
> displaying content. s_OpenCms is not allowed to login into workplace.
> 6. In MySQL, we created a timetable for store the time of publishing job. If
> user publish contents in m_OpenCms, m_OpenCms will update the table, record
> down the time of publishing job. Then m_MySQL will replicate this
> information to s_MySQL.
> 
> Due to the above setup, we have the below treatments regarding to OpenCms
> features.
> 1. Flexcache: We setup a schedule task in s_OpenCms to read the publishing
> job timetable. So if m_OpenCms published content, s_OpenCms will know some
> content is updated and clear the Flexcache. 

So time to live on s_OpenCms depends on the polling speed of the scheduled job.

> 2. Search Index: We setup a schedule task and run "Rebuild Index" in
> specific time. Assuming that date and time is in sync in Master and Slave
> machine.

That sounds OK.

> 3. Static Export: At the very beginning, we want it done as Flexcache.
> Following code is for purge the static export folder. But we find that
> sometimes (or very rarely) it cannot export the files again. So we DISABLE
> the static export finally. 

That's a pity.

>       CmsStaticExportManager manager = OpenCms.getStaticExportManager();
>       CmsEvent event = new CmsEvent(I_CmsEventListener.EVENT_UPDATE_EXPORTS,
> null);
>       manager.cmsEvent(event);  

So one question is: What costs more: OCEE Cluster or the time spent on implementing the above solution.

kind regards,

Achim