[infinispan-dev] Use of Inifnispan across data centers

[Bela Ban]

Galder Zamarreño wrote:
> On top of the issues you mentioned, you force all to have same 
> communications layer, TCP or UDP.

Correct

> Did you have a look at my Hot Rod presentation for JUDCon? 
> http://www.jboss.org/events/JUDCon/presentations.html. You might check 
> out the last bit of my presentation where I explained very briefly how 
> Infinispan accross data centres could potentially be written with 
> RemoteCacheStore hooking up different data centres via Hot Rod. Each 
> dc could be configured with JGroups TCP/UDP while the inter dc traffic 
> goes over Netty based TCP-NIO. An active/passive kind of layout would 
> be relatively easy to achieve this way.

Yes, this would probably work, too. However, there are a few drawbacks:

    * You have to configure an initial list of Hot Rod end points (in
      the example, in Bilbao). I guess this is minor though; once
      connected, clients get updated with the new membership list
    * When the coordinator in Bilbao crashes, someone else has to take
      over. During this transition you have to ensure that there are no
      lost or duplicate messages. This can be done with queuing and
      sequence numbers, plus retransmission, but then again, is this
      something you want to do in Hot Rod ?
    * Assume Boston is up and running, then Bilbao is started. How does
      Bilbao get the initial state of Boston ?


An unrelated question I have is what happens when the switch between 
Boston and Bilbao crashes ? I assume Hot Rod requires TCP underneath, so 
does it (or Netty) implement some heartbeating over the link ?


-- 
Bela Ban
Lead JGroups / Clustering Team
JBoss