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Posted to users@tomcat.apache.org by Kevin Phillips <ke...@yahoo.com> on 2008/09/17 18:04:22 UTC

session replication / cluster groups

Hi, I have tomcat clustering working well with an apache load balancer in front (sticky session). I have around 10 at the moment, and I soon need to add at least 20 to 30 more. The configuration for session replication is "all-to-all", using multicast. My aim is to reduce the session traffic between servers, so I am looking for alternatives. The Tomcat 6 book (o reilly) states:

"If you find that you have too many nodes in your cluster for all-to-all replication, you can [..] segment your network such that half of your nodes are in one group and half are in another group" (or implement primary/secondary clustering). 

I assume that segmentation is done by supplying a different multicast ip/port to the two groups, however, how will the apache (mod_proxy) know the right group member to fall to?


Regards,
K. Phillips

Re: session replication / cluster groups

Posted by Filip Hanik - Dev Lists <de...@hanik.com>.
you could use the BackupManager this only replicates data to one backup node

http://tomcat.apache.org/tomcat-6.0-doc/config/cluster-manager.html

and you can fail over to any node, it will fetch the backup from the 
backup node
Filip

Kevin Phillips wrote:
> Hi, I have tomcat clustering working well with an apache load balancer in front (sticky session). I have around 10 at the moment, and I soon need to add at least 20 to 30 more. The configuration for session replication is "all-to-all", using multicast. My aim is to reduce the session traffic between servers, so I am looking for alternatives. The Tomcat 6 book (o reilly) states:
>
> "If you find that you have too many nodes in your cluster for all-to-all replication, you can [..] segment your network such that half of your nodes are in one group and half are in another group" (or implement primary/secondary clustering). 
>
> I assume that segmentation is done by supplying a different multicast ip/port to the two groups, however, how will the apache (mod_proxy) know the right group member to fall to?
>
>
> Regards,
> K. Phillips
>
>
>
>       
>   


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RE: session replication / cluster groups

Posted by Paul McGurn <Pa...@logmein.com>.
I believe this segregation is typically done with instances of multiple load balancers.  I'm not an expert on the mod_jk stuff, but you'd probably want to implement this with multiple load balancers regardless, when you're getting up to that many instances.

Bear in mind that this piece of your setup is acting as a single point of failure in front of your Tomcat cluster.

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-----Original Message-----
From: Kevin Phillips [mailto:kevin.phillips83@yahoo.com]
Sent: Wednesday, September 17, 2008 12:04 PM
To: users@tomcat.apache.org
Subject: session replication / cluster groups

Hi, I have tomcat clustering working well with an apache load balancer in front (sticky session). I have around 10 at the moment, and I soon need to add at least 20 to 30 more. The configuration for session replication is "all-to-all", using multicast. My aim is to reduce the session traffic between servers, so I am looking for alternatives. The Tomcat 6 book (o reilly) states:

"If you find that you have too many nodes in your cluster for all-to-all replication, you can [..] segment your network such that half of your nodes are in one group and half are in another group" (or implement primary/secondary clustering).

I assume that segmentation is done by supplying a different multicast ip/port to the two groups, however, how will the apache (mod_proxy) know the right group member to fall to?


Regards,
K. Phillips




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