Patrick - Thank you, I'll proceed accordingly. -Todd
-Original Message-
From: Patrick Hunt [mailto:ph...@apache.org]
Sent: Wednesday, July 29, 2009 10:30 PM
To: zookeeper-user@hadoop.apache.org
Subject: Re: Zookeeper WAN Configuration
[Todd] What is the recommended policy regarding
Flavio, please enter a doc jira for this if there are no docs, it should
be in forrest, not twiki btw. It would be good if you could review the
current quorum docs (any type) and create a jira/patch that addresses
any/all shortfall.
Patrick
Flavio Junqueira wrote:
Todd, Some more answers.
This is the problem.
ALL writes go from the leader to all nodes and the transaction isn't done
until a quorum of machines have confirmed the write. Unless you have a
quorum in the central facility, then all writes be as slow as several
round-trips to the peripheral installations. This slows
Like most folks, our WAN is composed of various zones, some central
processing, some edge, some corp, and some in between (DMZs). In this
model, a given Zookeeper server will not have direct connectivity to all
of it's peers in the ensemble due to various security constraints. Is
this a problem?
Each member needs a connection to a quorum. The quorum is ceiling((N+1) /
2) members of the cluster.
This guarantees that network partition does not allow two leaders to go on
stamping out revisions independent of each other.
On Fri, Jul 24, 2009 at 4:23 PM, Todd Greenwood
Servers in a quorum need to be able to talk to each other to elect a
leader. Once a leader is elected, followers only talk to the leader.
Of course, if the leader fails, servers in some quorum will need to
talk to each other again. If no quorum can be formed, the system is
stalled.
responds to ensemble with update + transaction id
-Todd
-Original Message-
From: Flavio Junqueira [mailto:f...@yahoo-inc.com]
Sent: Friday, July 24, 2009 4:50 PM
To: zookeeper-user@hadoop.apache.org
Subject: Re: Zookeeper WAN Configuration
Just a few quick observations:
On Jul 24, 2009