Thanks Ted,

frankly speaking, your answer makes me nervous about upgrade Zookeeper
server.  Hope the developers of Zookeeper thinking about it. I think
Zookeeper is very cool. But it isn't good enough for online systems if it
cannot be upgraded without losing existed data.


On Sat, Jun 27, 2009 at 3:13 PM, Ted Dunning <> wrote:

> In general for changes like this, you need to be running more than one
> server in a cluster to avoid losing state such as the ephemeral nodes.
> I can't say for certain that the 3.1.1 to 3.2 change can be done this way,
> but most upgrades can be done by stopping one server at a time, changing
> the software and config and restarting it.  Then you move on to the next.
> This will cause a connection loss event for each client eventually, but it
> should
> not cause any sessions to expire.
> Don't do this until somebody says something for certain that 3.1.1 can
> change to 3.2 within a cluster.
> On Fri, Jun 26, 2009 at 7:16 PM, Qian Ye <> wrote:
> > 2. How to upgrade from 3.1.1 to 3.2.0 properly. Just stop the old server
> > and
> > start the new server would be OK? Will this operation influence the old
> > ephemeral znodes? Is there a perfect upgrade plan´╝č
> >

With Regards!

Ye, Qian
Made in Zhejiang University

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