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stone commented on CASSANDRA-12257: ----------------------------------- need measure the latency between DC real time so we can look back the data. > data consistency of multi datacenter > ------------------------------------- > > Key: CASSANDRA-12257 > URL: https://issues.apache.org/jira/browse/CASSANDRA-12257 > Project: Cassandra > Issue Type: Improvement > Components: Coordination > Reporter: stone > > Environment: > serveral active-active cassandra datacenter. > set write consistency level=local_quorum to get a high resquest response. > Concern: > we dont know the time of the data arrive other datacenter. > we dont know the size of data that need to be transferred to other > datacenter. > Thought: > 1.we can get the latency with ping or other monitor tool,but it can not > represent the latency of cassandra data to be transferred from one dc to > another dc. > 2.we can measure the latency between dc.but there is a accumulated value from > node started,it cannot represent the latency now. > https://issues.apache.org/jira/browse/CASSANDRA-11569 > Scenanio: > one project need to collect information from sensors,which in different > region.2 datacenter,DC1,DC2.sensor1,sensor2 in DC1 region.sensor3,sensor4 in > DC2. > one client in DC1,pull data every 10 minutes. > 1.sensor3 in DC2 write a record to DC2 at 8:59:55 ,and arrived DC1 at 9:00:05 > 2.client in DC1 pull data at 9:00,it should get the record,but it cannot as > the > record have not arrive DC1. > 3.then client in DC1 will pull data at 9:10.it also can not get the record as > it will pull data from 9:00---9:10,but the record created on 8:59:55 > so we will miss the record. -- This message was sent by Atlassian JIRA (v6.3.4#6332)