Yes. In ZooKeeper reads are local. In Cassandra, for example, reads are quorum usually.
==================== Jordan Zimmerman > On May 9, 2018, at 8:40 PM, Prasanth Mathialagan > <[email protected]> wrote: > > For reads, is Quorum necessary? Reads are served from local the local > replica, right? > > On Wed, May 9, 2018 at 8:29 AM, Jordan Zimmerman <[email protected] >> wrote: > >> A quorum means (n/2)+1 - In a 3 node cluster that is 2. So, if 2 servers >> are up you can achieve quorum. >> >>> we need odd >>> numbers in order to form a quorum >> >> The "odd" in this formula refers to the number of configured servers not >> how many are running at a given time. That's the reasoning for quorum in >> the first place. Quorum I/O ensures that a majority of nodes is referenced >> for reads or writes (in ZooKeeper writes are what matter for quorum). >> >> -Jordan >> >>> On May 9, 2018, at 10:26 AM, Kaushal Shriyan <[email protected]> >> wrote: >>> >>> Hi, >>> >>> In a ensemble of 3 nodes with 1 leader and 2 followers, if the leader >> goes >>> down then two servers can elect a leader among themselves. But we need >> odd >>> numbers in order to form a quorum. I am confused. Please correct me if i >> am >>> understanding it wrong. >>> >>> Any help will be highly appreciable >>> >>> Best Regards, >>> >>> Kaushal >> >>
