Hi Thomas, In the scenario you describe, 1 and 2 won't make any progress as they are not part of a component that contains a quorum (a majority in this current implementation). Servers 3,4,5 will elect a leader (if they don't have one yet), and will make progress independently. Once the segmentation heals, 1 and 2 will synchronize with the current leader.
Thanks, -Flavio > -----Original Message----- > From: Kiesslich, Thomas [mailto:[EMAIL PROTECTED] > Sent: Monday, November 17, 2008 2:04 PM > To: [email protected] > Subject: AW: Dynamic server management? > > Hi Flavio, > > Thank you for the information. > > So how do you handle than the following scenario? > You have 5 servers and temporary network segmentation, where server 1 and > 2 cannot talk to 3,4 and 5. Will server 1 and 2 do a new leader election > for their partition, as well server 3,4 and 5 for their partition? If yes, > how do they synchronize if they can reach each other again? > > > Mit freundlichen Grüßen / With best regards > Thomas Kießlich > > Siemens Enterprise Communications GmbH & Co. KG > HiPath Applications > > SEN LIP DA 11 > Schertlinstr. 8 > 81379 Munich, Germany > > -----Ursprüngliche Nachricht----- > Von: Flavio Junqueira [mailto:[EMAIL PROTECTED] > Gesendet: Montag, 17. November 2008 13:49 > An: [email protected] > Betreff: RE: Dynamic server management? > > Hi Thomas, We currently don't have such a feature of adding and removing > servers dynamically, although we would like to, so we'll have it > eventually. > > Without a dynamic mechanism for adding and removing servers, your example > is > problematic. Suppose that you configure your ensemble to have 3 servers, > and > then you start only one. Your single server would say: "Hey, I'm alone so > I > should make progress independently". This is reasonable, right? Well, not > really, because you can have the following alternative execution. You > start > your three servers, but there is a temporary network partition and server > 1 > cannot talk to servers 2 and 3. Consequently, server 1 will make progress > independently of 2 and 3, and their state will diverge. > > Hope it helps. > > -Flavio > > > -----Original Message----- > > From: Kiesslich, Thomas [mailto:[EMAIL PROTECTED] > > Sent: Monday, November 17, 2008 11:46 AM > > To: [email protected] > > Subject: Dynamic server management? > > > > Hi all, > > > > I am evaluating ZooKeeper as a discovery protocol. I want to change the > > number of servers that build up ensemble during runtime of an existing > > number servers. Is that possible or do I have to change the > configuration > > and restart all servers? I found that if you have 3 servers configured > and > > startup the first it is continously looking for the at least one other > > server. Is it really necessary to do that? If the first server does not > > find anyone else, it could elect itself as the leader. If the next > server > > starts up the can redo the election I guess. > > Could you please help me with these questions? Thank you. > > > > > > > > Mit freundlichen Grüßen / With best regards > > Thomas Kießlich > > > > Siemens Enterprise Communications GmbH & Co. KG > > HiPath Applications > > > > SEN LIP DA 11 > > Schertlinstr. 8 > > 81379 Munich, Germany > > > > Phone: +49 (89) 722-32483 > > Fax: +49 (89) 722-40560 > > Email: [EMAIL PROTECTED] > > > > Communication for the open minded > > www.siemens.de/open > > www.siemens.com/open > > > > Siemens Enterprise Communications GmbH & Co. KG > > Managing Directors: Andreas Bernhardt, Reinhard Benditte, > > Gerhard Otterbach, Thomas Zimmermann > > Registered offices: Munich > > Commercial registry Munich, HRA 88546 > > WEEE-Reg.-No. DE 27980375 > > General Partner: > > Siemens Enterprise Communications Management GmbH > > Registered offices: Munich > > Commercial registry: Munich, HRB 163415 > > > > Wichtiger Hinweis: Diese Information ist für den Gebrauch durch die > Person > > oder die Firma/Organisation bestimmt, die in der Empfängeradresse > benannt > > ist. Wenn Sie nicht der angegebene Empfänger sind, nehmen Sie bitte zur > > Kenntnis, daß Weitergabe, Kopieren, Verteilung oder Nutzung des Inhalts > > dieser Email-Übertragung unzulässig ist. Falls Sie diese Email > irrtümlich > > erhalten haben, benachrichtigen Sie den Absender bitte unverzüglich > > telefonisch oder durch eine Email. Vielen Dank. > > > > Important Note: This e-mail may contain trade secrets or privileged, > > undisclosed or otherwise confidential information. If you have received > > this e-mail in error, you are hereby notified that any review, copying > or > > distribution of it is strictly prohibited. Please inform us immediately > > and destroy the original transmittal. Thank you for your cooperation. > > >
