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From Bryan Talbot <btal...@aeriagames.com>
Subject Re: Cluster not accepting insert while one node is down
Date Thu, 14 Feb 2013 16:30:18 GMT
Generally data isn't written to whatever node the client connects to.  In
your case, a row is written to one of the nodes based on the hash of the
row key.  If that one replica node is down, it won't matter which
coordinator node you attempt a write with CL.ONE: the write will fail.

If you want the write to succeed, you could do any one of: write with
CL.ANY, increase RF to 2+, write using a row key that hashes to an UP node.

-Bryan



On Thu, Feb 14, 2013 at 2:06 AM, Alain RODRIGUEZ <arodrime@gmail.com> wrote:

> I will let commiters or anyone that has knowledge on Cassandra internal
> answer this.
>
> From what I understand, you should be able to insert data on any up node
> with your configuration...
>
> Alain
>
>
> 2013/2/14 Traian Fratean <traian.fratean@gmail.com>
>
>> You're right as regarding data availability on that node. And my config,
>> being the default one, is not suited for a cluster.
>> What I don't get is that my 67 node was down and I was trying to insert
>> in 66 node, as can be seen from the stacktrace. Long story short: when node
>> 67 was down I could not insert into any machine in the cluster. Not what I
>> was expecting.
>>
>> Thank you for the reply!
>> Traian.
>>
>> 2013/2/14 Alain RODRIGUEZ <arodrime@gmail.com>
>>
>>> Hi Traian,
>>>
>>> There is your problem. You are using RF=1, meaning that each node is
>>> responsible for its range, and nothing more. So when a node goes down, do
>>> the math, you just can't read 1/5 of your data.
>>>
>>> This is very cool for performances since each node owns its own part of
>>> the data and any write or read need to reach only one node, but it removes
>>> the SPOF, which is a main point of using C*. So you have poor availability
>>> and poor consistency.
>>>
>>> An usual configuration with 5 nodes would be RF=3 and both CL (R&W) =
>>> QUORUM.
>>>
>>> This will replicate your data to 2 nodes + the natural endpoints (total
>>> of 3/5 nodes owning any data) and any read or write would need to reach at
>>> least 2 nodes before being considered as being successful ensuring a strong
>>> consistency.
>>>
>>> This configuration allow you to shut down a node (crash or configuration
>>> update/rolling restart) without degrading the service (at least allowing
>>> you to reach any data) but at cost of more data on each node.
>>>
>>> Alain
>>>
>>>
>>> 2013/2/14 Traian Fratean <traian.fratean@gmail.com>
>>>
>>>> I am using defaults for both RF and CL. As the keyspace was created
>>>> using cassandra-cli the default RF should be 1 as I get it from below:
>>>>
>>>> [default@TestSpace] describe;
>>>> Keyspace: TestSpace:
>>>>   Replication Strategy:
>>>> org.apache.cassandra.locator.NetworkTopologyStrategy
>>>>   Durable Writes: true
>>>>     Options: [datacenter1:1]
>>>>
>>>> As for the CL it the Astyanax default, which is 1 for both reads and
>>>> writes.
>>>>
>>>> Traian.
>>>>
>>>>
>>>> 2013/2/13 Alain RODRIGUEZ <arodrime@gmail.com>
>>>>
>>>>> We probably need more info like the RF of your cluster and CL of your
>>>>> reads and writes. Maybe could you also tell us if you use vnodes or not.
>>>>>
>>>>> I heard that Astyanax was not running very smoothly on 1.2.0, but a
>>>>> bit better on 1.2.1. Yet, Netflix didn't release a version of Astyanax
for
>>>>> C*1.2.
>>>>>
>>>>> Alain
>>>>>
>>>>>
>>>>> 2013/2/13 Traian Fratean <traian.fratean@gmail.com>
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> I have a cluster of 5 nodes running Cassandra 1.2.0 . I have a Java
>>>>>> client with Astyanax 1.56.21.
>>>>>> When a node(10.60.15.67 - *diiferent* from the one in the stacktrace
>>>>>> below) went down I get TokenRandeOfflineException and no other data
gets
>>>>>> inserted into *any other* node from the cluster.
>>>>>>
>>>>>> Am I having a configuration issue or this is supposed to happen?
>>>>>>
>>>>>>
>>>>>> com.netflix.astyanax.connectionpool.impl.CountingConnectionPoolMonitor.trackError(CountingConnectionPoolMonitor.java:81)
>>>>>> -
>>>>>> com.netflix.astyanax.connectionpool.exceptions.TokenRangeOfflineException:
>>>>>> TokenRangeOfflineException: [host=10.60.15.66(10.60.15.66):9160,
>>>>>> latency=2057(2057), attempts=1]UnavailableException()
>>>>>> com.netflix.astyanax.connectionpool.exceptions.TokenRangeOfflineException:
>>>>>> TokenRangeOfflineException: [host=10.60.15.66(10.60.15.66):9160,
>>>>>> latency=2057(2057), attempts=1]UnavailableException()
>>>>>> at
>>>>>> com.netflix.astyanax.thrift.ThriftConverter.ToConnectionPoolException(ThriftConverter.java:165)
>>>>>>  at
>>>>>> com.netflix.astyanax.thrift.AbstractOperationImpl.execute(AbstractOperationImpl.java:60)
>>>>>> at
>>>>>> com.netflix.astyanax.thrift.AbstractOperationImpl.execute(AbstractOperationImpl.java:27)
>>>>>>  at
>>>>>> com.netflix.astyanax.thrift.ThriftSyncConnectionFactoryImpl$1.execute(ThriftSyncConnectionFactoryImpl.java:140)
>>>>>> at
>>>>>> com.netflix.astyanax.connectionpool.impl.AbstractExecuteWithFailoverImpl.tryOperation(AbstractExecuteWithFailoverImpl.java:69)
>>>>>>  at
>>>>>> com.netflix.astyanax.connectionpool.impl.AbstractHostPartitionConnectionPool.executeWithFailover(AbstractHostPartitionConnectionPool.java:255)
>>>>>>
>>>>>>
>>>>>>
>>>>>> Thank you,
>>>>>> Traian.
>>>>>>
>>>>>
>>>>>
>>>>
>>>
>>
>

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