[opencms-dev] FW: opencms-dev Digest, Vol 52, Issue 4

[Tim Howland]

 Hey Collin-

Here are some previous threads on clustering, from my experiences on
getting blindsided by a client with crazy high traffic loads.

http://mail.opencms.org/pipermail/opencms-dev/2003q2/005485.html

http://mail.opencms.org/pipermail/opencms-dev/2004q2/010554.html


Basically, setting up parallel tomcat servers works great, and you can
pretty much rely on the mod_jk load balancer to cross connect your
apache instances to the tomcats. You'll want to arrange mysql
replication and some sort of heartbeat arrangement to get failover down
to the mysql level, but mysql failures seem rare in my experience, if
you're on an old enough version. 

However, there is a problem with this approach when working with dynamic
content instead of static exports; when you publish,  the caches get out
of sync, and you end up with old content on one server for a while. You
need to flush caches on your standby server whenever you publish. We did
this by giving clients a CGI that called the ant reload script on our
standby server, but this is obviously a bit drastic. If you do static
exports, you could have a cron job that called rsync periodically and
distributed your changes around your webapps.

I've just started playing with openCMS 6 and don't know if there's a way
we can trap the publish event yet on a remote server. (I've been sucked
into the new structured forms stuff- great work guys!)

HTH,

Tim





Message: 21
Date: Wed, 03 Aug 2005 16:26:38 -0400
From: Collin McClendon <collin.mcclendon at digiconasp.com>
Subject: [opencms-dev] Clustering / Load Balancing OpenCMS servers?
To: The OpenCms mailing list <opencms-dev at opencms.org>
Message-ID: <42F1287E.2000801 at digiconasp.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

We have a separate DB server here and want to try load balancing the 
front end servers which will just run OpenCMS.
Has anyone tried doing something of this sort? What would be the effects

of having multiple users logged into the systems and editing content? 
How can we scale this product if we can't get beyond 1 front end server 
is beyond me, I hope someone has some ideas. I've gotten this far with 
OpenCMS, and its been a good product, but if we can't find a way to 
scale, we might have to look at another CMS (not such a good thing now 
that we are almost to production).
Thanks for any advice/help,
Collin

-- 
Collin McClendon
Sr. Microsoft Systems Engineer
Digicon Corporation
collin.mcclendon at digiconasp.com


------------------------------

Message: 22
Date: Wed, 03 Aug 2005 22:51:54 +0200
From: Thomas Maerz <thomasmaerz at gmx.de>
Subject: Re: [opencms-dev] Clustering / Load Balancing OpenCMS
	servers?
To: The OpenCms mailing list <opencms-dev at opencms.org>
Message-ID: <84slxqzqtx.fsf at gmx.de>
Content-Type: text/plain; charset=us-ascii

Collin McClendon <collin.mcclendon at digiconasp.com> writes:

> We have a separate DB server here and want to try load balancing the 
> front end servers which will just run OpenCMS.
> Has anyone tried doing something of this sort? What would be the
effects 
> of having multiple users logged into the systems and editing content? 
> How can we scale this product if we can't get beyond 1 front end
server 
> is beyond me, I hope someone has some ideas. I've gotten this far with

> OpenCMS, and its been a good product, but if we can't find a way to 
> scale, we might have to look at another CMS (not such a good thing now

> that we are almost to production).

Search the archive for load balancing and clearing the cache after
publish.
There's somewhere a thread that explains some details.


Regards,
Thomas


End of opencms-dev Digest, Vol 52, Issue 4
******************************************