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From Nate McCall <n...@datastax.com>
Subject Re: HUnavailableException: : May not be enough replicas present to handle consistency level.
Date Fri, 02 Sep 2011 20:22:23 GMT
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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