Re: [infinispan-dev] X-datacentre replication: design suggestions
----- Original Message -----
From: "Sanne Grinovero" <sanne(a)infinispan.org>
To: "infinispan -Dev List" <infinispan-dev(a)lists.jboss.org>
Sent: Monday, February 13, 2012 8:06:03 AM
Subject: Re: [infinispan-dev] X-datacentre replication: design suggestions
On 10 February 2012 19:17, Dan Berindei <dan.berindei(a)gmail.com>
wrote:
> Mircea was saying that we'd only send over committed modifications,
> so
> no locking RPCs that need to be synchronous.
I understand the performance cost would be otherwise high, but is
this
not defeating the purpose?
I would expect as a user that - if I need cross-datacenter
replication
- I would get a strong guarantee that committed data is safe in both
locations, not that some might still need to be sent.
If you configure an *sync*
bridge then you'd get the confirmation during the commit. What you don't get by
participating in the preapre is consistency guarnatees for two tx writing to same data in
different datacenters - but not sure we want to support that?
So I would expect that - for transactional operations only - the
other
locations participate in the prepare phase.
If we go for async replication, won't we need as well some way to
guarantee that the other replicas apply changes in the correct order?
Can you
please detail on this scenario?
About the cons in #3, it states
"the state transfer needs to be customized to send all cluster's
state
through the end-point."
Why? Can't we have each node connect directly? No endpoint -> no
overloading.
that's what #2 does. Possible, but it has its cons, mainly the
number of x-site connections. See bela's comment in a previous email and Erik's
comment here: https://community.jboss.org/wiki/CrossDatacenterReplication-Design