Hi Maxime - When a quorum of ZooKeeper servers have failed, the service stops being available - you cannot write or read to any item. Once a quorum returns to operation, the ensemble recovers automatically and continues where it left off. There is the same requirement that a quorum of servers must see every write.
We (and myself in particular) are working on dynamic cluster membership, see https://issues.apache.org/jira/browse/ZOOKEEPER-107 and the related https://issues.apache.org/jira/browse/ZOOKEEPER-368. Henry On Wed, Jul 1, 2009 at 3:07 PM, Maxime Caron <maxime.ca...@gmail.com> wrote: > I was investigating scalaris (http://code.google.com/p/scalaris/) but > found > it does not support a persistent storage. > In their faq they say it cant be done because they assume that a majority > of > the replicas of an item is always available. > If this precondition is violated, a majority of the nodes with replicas of > an item x is not available, the item cannot be changed. It is lost. > Persistent storage cannot help directly. > So i would like to understand if zookeeper work the same way or their is a > recovery model for when the majority of the goes down and then back up. > > > Unlike zookeeper with scalaris servers can be added or removed on the fly > without any service downtime. > From what i can understand in zookeeper you need to have a fixed server > list > that every body share. > Would it be possible to add on the fly server addition and removal to > zookeeper? >