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From Tamar Fraenkel <ta...@tok-media.com>
Subject Re: consistency level question
Date Wed, 21 Mar 2012 06:56:44 GMT
Thanks,

*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 Mon, Mar 19, 2012 at 11:49 AM, aaron morton <aaron@thelastpickle.com>wrote:

> Some information on node failures, consistency levels and availability
> http://thelastpickle.com/2011/06/13/Down-For-Me/
>
> Cheers
>
>
>   -----------------
> Aaron Morton
> Freelance Developer
> @aaronmorton
> http://www.thelastpickle.com
>
> On 19/03/2012, at 1:08 PM, Watanabe Maki wrote:
>
> Yes, read and write won't fail with single node failure.
> But your read may return old data.
>
> maki
>
> On 2012/03/19, at 1:08, Caleb Rackliffe <caleb@steelhouse.com> wrote:
>
> That sounds right to me :)
>
> *
> Caleb Rackliffe | Software Developer
> M 949.981.0159 | caleb@steelhouse.com
> **
>  <EB2FF764-478C-4966-9B0A-E7B76D6AD7DC[18].png>
> *
>
> From: Tamar Fraenkel <tamar@tok-media.com>
> Reply-To: "user@cassandra.apache.org" <user@cassandra.apache.org>
> Date: Sun, 18 Mar 2012 04:20:58 -0400
> To: "user@cassandra.apache.org" <user@cassandra.apache.org>
> Subject: Re: consistency level question
>
> 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
>
> <tokLogo.png>
>
> 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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