[jira] [Resolved] (CASSANDRA-2456) using NTS, you get a an error (datacenter has no more endpoints) when there are no nodes in a DC

["Jonathan Ellis (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CASSANDRA-2456?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jonathan Ellis resolved CASSANDRA-2456.
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    Resolution: Not A Problem

It's an error to specify a nonzero replication factor for a DC that has zero nodes in it.  Use DC3:0 if you want to perform writes before you actually have nodes in it.

> using NTS, you get a an error (datacenter has no more endpoints) when there are no nodes in a DC
> ------------------------------------------------------------------------------------------------
>
>                 Key: CASSANDRA-2456
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-2456
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>    Affects Versions: 0.7.4
>            Reporter: Josep M. Blanquer
>
> If one creates a brand new DC in the NTS (NetworkTopologyStrategy) for which no node has been seen, you'll get exceptions for any write consistency level after that.
> Note that you don't get the problem if you have a DC for which you have all nodes marked 'down'. It seems just a bug when there are 0 nodes seen in the DC.
> To reproduce:
> 1- Go to a running NTS cluster, and add a new DC in the strategy options. I.e., from the console, assuming you have DC1 and DC2 normally, add a DC3:
> update keyspace WhateverKeyspace with strategy_options=[{DC1:2,DC2:1,DC3:1}];    
> 2- Try to write...and you'll get:
> java.lang.IllegalStateException: datacenter (DC3) has no more endpoints, (1) replicas still needed
> but if you boot a node in DC3, and then stop it...the writes will succeed.
> I believe it should always succeed to be consistent?
> Otherwise one needs to boot nodes in the right DCs, get the snitches propagated and all...all before changing the NTS strategy options. Maybe that's fine...but it feels inconsistent with succeeding when a whole DC is down.

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