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From Oleg Tsvinev <oleg.tsvi...@gmail.com>
Subject Re: HUnavailableException: : May not be enough replicas present to handle consistency level.
Date Fri, 02 Sep 2011 20:35:31 GMT
from http://www.datastax.com/docs/0.8/consistency/index:

<A “quorum” of replicas is essentially a majority of replicas, or RF /
2 + 1 with any resulting fractions rounded down.>

I have RF=2, so majority of replicas is 2/2+1=2 which I have after 3rd
node goes down?

On Fri, Sep 2, 2011 at 1:22 PM, Nate McCall <nate@datastax.com> wrote:
> It looks like you only have 2 replicas configured in each data center?
>
> If so, LOCAL_QUORUM cannot be achieved with a host down same as with
> QUORUM on RF=2 in a single DC cluster.
>
> On Fri, Sep 2, 2011 at 1:40 PM, Oleg Tsvinev <oleg.tsvinev@gmail.com> wrote:
>> I believe I don't quite understand semantics of this exception:
>>
>> me.prettyprint.hector.api.exceptions.HUnavailableException: : May not
>> be enough replicas present to handle consistency level.
>>
>> Does it mean there *might be* enough?
>> Does it mean there *is not* enough?
>>
>> My case is as following - I have 3 nodes with keyspaces configured as following:
>>
>> Replication Strategy: org.apache.cassandra.locator.NetworkTopologyStrategy
>> Durable Writes: true
>> Options: [DC2:2, DC1:2]
>>
>> Hector can only connect to nodes in DC1 and configured to neither see
>> nor connect to nodes in DC2. This is for replication by Cassandra
>> means, asynchronously between datacenters DC1 and DC2. Each of 6 total
>> nodes can see any of the remaining 5.
>>
>> and inserts with LOCAL_QUORUM CL work fine when all 3 nodes are up.
>> However, this morning one node went down and I started seeing the
>> HUnavailableException: : May not be enough replicas present to handle
>> consistency level.
>>
>> I believed if I have 3 nodes and one goes down, two remaining nodes
>> are sufficient for my configuration.
>>
>> Please help me to understand what's going on.
>>
>

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