Thanks Mahadev, your information is really helpful :-)

On Wed, Jul 1, 2009 at 12:14 AM, Mahadev Konar <maha...@yahoo-inc.com>wrote:

> Hi Qian,
>  Sorry for the delayed response. ZooKeeper guarantees that their is
> backwards compatibility with minor releases. So, 3.2* is backwards
> compatible with 3.1*. So, what Ted mentions below related to rolling
> upgrade
> should work.
>
> Hope this helps.
> Thanks
> Mahadev
>
>
> Ted Dunning:
>
> A rolling update works very well for that.  You can also change the number
> of nodes in the cluster.
>
> To do this, you replace the config files on the surviving servers and on
> the
> new server.
>
> Then take down the one that is leaving the cluster and then one by one
> restart the servers that will remain in the cluster.  Then start the new
> server.
>
> If you only have 3 ZK servers, you might want to do the upgrade in two
> steps
> if you are totally paranoid about running with just 2 servers in your
> cluster.  In that scenario, you would add the new server to the config and
> restart each of the 3 ZK servers and staring the new one.  That gives you a
> ZK cluster with 4 servers.  Another rolling update can reconfigure it to
> have only the 3 servers you want.
>
> Make sure you leave several seconds between restarting each server.  That
> will give the cluster time to calm down and do any necessary leader
> elections
>
>
> On 6/28/09 11:03 PM, "Qian Ye" <yeqian....@gmail.com> wrote:
>
> > A related question.  If I have run a Zookeeper service with many
> ephemeral
> > znodes on five servers, then I want to replace one of the servers by a
> new
> > one, and the new server has a new IP. How can I do the job without any
> loss
> > of data ?
> >
> > Thanks
> >
> >
> > On Mon, Jun 29, 2009 at 9:24 AM, Qian Ye <yeqian....@gmail.com> wrote:
> >
> >> Thanks for the explanation, it sounds great.
> >>
> >> It seems that I should study more on Zookeeper :-)
> >>
> >> regards
> >>
> >>
> >> On Mon, Jun 29, 2009 at 2:15 AM, Ted Dunning <ted.dunn...@gmail.com
> >wrote:
> >>
> >>> I don't think you should be very nervous at all.
> >>>
> >>> There are two questions:
> >>>
> >>> 1) can 3.1.1 go to 3.2 with no down time.  This is very likely, but a
> >>> wiser
> >>> head than mine should have final say
> >>>
> >>> 2) can 3.1.1 go to 3.2 with < 1 minute of downtime.  The is for sure.
> >>>
> >>> Neither option involves data loss.
> >>>
> >>> ZK is actually really really good for HA operations.
> >>>
> >>> On Sun, Jun 28, 2009 at 4:55 AM, Qian Ye <yeqian....@gmail.com> wrote:
> >>>
> >>>> your answer makes me nervous about upgrade Zookeeper
> >>>> server
> >>>>
> >>>
> >>
> >>
> >>
> >> --
> >> With Regards!
> >>
> >> Ye, Qian
> >> Made in Zhejiang University
> >>
> >>
> >
>
>


-- 
With Regards!

Ye, Qian
Made in Zhejiang University

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