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From Tamar Fraenkel <ta...@tok-media.com>
Subject Re: consistency level question
Date Sun, 18 Mar 2012 08:20:58 GMT
Thanks!
I updated replication factor to 2, and now when I took one node down all
continued running (I did see Hector complaining on the node being down),
but things were saved to db and read from it.

Just so I understand, now, having replication factor of 2, if I have 2 out
of 3 nodes running all my read and writes with CL=1 should work, right?


*Tamar Fraenkel *
Senior Software Engineer, TOK Media

[image: Inline image 1]

tamar@tok-media.com
Tel:   +972 2 6409736
Mob:  +972 54 8356490
Fax:   +972 2 5612956





On Sun, Mar 18, 2012 at 9:57 AM, Watanabe Maki <watanabe.maki@gmail.com>wrote:

> Because your RF is 1, so you need all nodes up.
>
> maki
>
>
> On 2012/03/18, at 16:15, Tamar Fraenkel <tamar@tok-media.com> wrote:
>
> Hi!
> I have a 3 node cassandra cluster.
> I use Hector API.
>
> I give hecotr one of the node's IP address
> I call setAutoDiscoverHosts(true) and setRunAutoDiscoveryAtStartup(true).
>
> The describe on one node returns:
>
> Replication Strategy: org.apache.cassandra.locator.SimpleStrategy
>   Durable Writes: true
>     Options: [replication_factor:1]
>
> The odd thing is that when I take one of the nodes down, expecting all to
> continue running smoothly, I get exceptions of the format seen bellow, and
> no read or write succeeds. When I bring the node back up, exceptions stop
> and read and write resumes.
>
> Any idea or explanation why this is the case?
> Thanks!
>
>
> me.prettyprint.hector.api.exceptions.HUnavailableException: : May not be
> enough replicas present to handle consistency level.
>         at
> me.prettyprint.cassandra.service.ExceptionsTranslatorImpl.translate(ExceptionsTranslatorImpl.java:66)
>         at
> me.prettyprint.cassandra.service.KeyspaceServiceImpl$7.execute(KeyspaceServiceImpl.java:285)
>         at
> me.prettyprint.cassandra.service.KeyspaceServiceImpl$7.execute(KeyspaceServiceImpl.java:268)
>         at
> me.prettyprint.cassandra.service.Operation.executeAndSetResult(Operation.java:103)
>         at
> me.prettyprint.cassandra.connection.HConnectionManager.operateWithFailover(HConnectionManager.java:246)
>         at
> me.prettyprint.cassandra.service.KeyspaceServiceImpl.operateWithFailover(KeyspaceServiceImpl.java:131)
>         at
> me.prettyprint.cassandra.service.KeyspaceServiceImpl.getSlice(KeyspaceServiceImpl.java:289)
>         at
> me.prettyprint.cassandra.model.thrift.ThriftSliceQuery$1.doInKeyspace(ThriftSliceQuery.java:53)
>         at
> me.prettyprint.cassandra.model.thrift.ThriftSliceQuery$1.doInKeyspace(ThriftSliceQuery.java:49)
>         at
> me.prettyprint.cassandra.model.KeyspaceOperationCallback.doInKeyspaceAndMeasure(KeyspaceOperationCallback.java:20)
>         at
> me.prettyprint.cassandra.model.ExecutingKeyspace.doExecute(ExecutingKeyspace.java:85)
>         at
> me.prettyprint.cassandra.model.thrift.ThriftSliceQuery.execute(ThriftSliceQuery.java:48)
>         at
> me.prettyprint.cassandra.service.ColumnSliceIterator.hasNext(ColumnSliceIterator.java:60)
>         at
>
>
> *Tamar Fraenkel *
> Senior Software Engineer, TOK Media
>
> <tokLogo.png>
>
>
> tamar@tok-media.com
> Tel:   +972 2 6409736
> Mob:  +972 54 8356490
> Fax:   +972 2 5612956
>
>
>
>

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