It's a bit more involved than that. C* uses a "Phi accrual failure
detector":https://docs.datastax.com/en/cassandra/3.x/cassandra/architecture/archDataDistributeFailDetect.html
https://github.com/apache/cassandra/blob/trunk/conf/cassandra.yaml#L878See also
https://dspace.jaist.ac.jp/dspace/bitstream/10119/4784/1/IS-RR-2004-010.pdf
Best,
Romain
Le Jeudi 11 août 2016 17h02, jean paul <researche...@gmail.com> a écrit :
Hi, thanks a lot for answer :)
Gossip is a peer-to-peer communication protocol in which nodes periodically
exchange state information about themselves and about other nodes they know
about.
unreachableNodes = probe.getUnreachableNodes(); ---> i.e if nodedon't
publish heartbeats on x seconds (using gossip protocol), it's therefore marked
'DN: down' ?
That's it?
2016-08-11 13:51 GMT+01:00 Romain Hardouin <romainh...@yahoo.fr>:
Hi Jean Paul,
Yes, the gossiper is used. Example with down nodes:1. The status command
retrieve unreachable nodes from a NodeProbe instance: https://github.com/
apache/cassandra/blob/trunk/ src/java/org/apache/cassandra/
tools/nodetool/Status.java#L64
2. The NodeProbe list comes from a StorageService proxy:
https://github.com/apache/ cassandra/blob/trunk/src/java/
org/apache/cassandra/tools/ NodeProbe.java#L4383. The proxy calls the Gossiper
singleton: https://github.com/ apache/cassandra/blob/trunk/
src/java/org/apache/cassandra/ service/StorageService.java# L2681
Best,
Romain
Le Jeudi 11 août 2016 14h16, jean paul <researche...@gmail.com> a écrit :
Hi all,
$nodetool status
Datacenter: datacenter1
=======================
Status=Up/Down
|/ State=Normal/Leaving/Joining/ Moving
-- Address Load Tokens Owns (effective) Host ID
Rack
UN 127.0.0.1 83.05 KB 256 100.0% 460ddcd9-1ee8-48b8-a618-
c076056aad07 rack1
The nodetool command shows the status of the node (UN=up,DN=down):
Please i'd like to know how this command works and is it based on gossip
protocol or not ?
Thank you so much for explanations.Best regards.
