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From Ajay Garg <ajaygargn...@gmail.com>
Subject Re: Is replication possible with already existing data?
Date Sat, 24 Oct 2015 04:42:55 GMT
Thanks Steve and Michael.

Simply uncommenting "initial_token" did the trick !!!

Right now, I was evaluating replication, for the case when everything is a
clean install.
Will now try my hands on integrating/starting replication, with
pre-existing data.


Once again, thanks a ton for all the help guys !!!


Thanks and Regards,
Ajay

On Sat, Oct 24, 2015 at 2:06 AM, Steve Robenalt <srobenalt@highwire.org>
wrote:

> Hi Ajay,
>
> Please take a look at the cassandra.yaml configuration reference regarding
> intial_token and num_tokens:
>
>
> http://docs.datastax.com/en/cassandra/2.1/cassandra/configuration/configCassandra_yaml_r.html?scroll=reference_ds_qfg_n1r_1k__initial_token
>
> This is basically what Michael was referring to in his earlier message.
> Setting an initial token overrode your num_tokens setting on initial
> startup, but after initial startup, the initial token setting is ignored,
> so num_tokens comes into play, attempting to start up with 256 vnodes.
> That's where your error comes from.
>
> It's likely that all of your nodes started up like this since you have the
> same config on all of them (hopefully, you at least changed initial_token
> for each node).
>
> After reviewing the doc on the two sections above, you'll need to decide
> which path to take to recover. You can likely bring the downed node up by
> setting num_tokens to 1 (which you'd need to do on all nodes), in which
> case you're not really running vnodes. Alternately, you can migrate the
> cluster to vnodes:
>
>
> http://docs.datastax.com/en/cassandra/2.1/cassandra/configuration/configVnodesProduction_t.html
>
> BTW, I recommend carefully reviewing the cassandra.yaml configuration
> reference for ANY change you make from the default. As you've experienced
> here, not all settings are intended to work together.
>
> HTH,
> Steve
>
>
>
> On Fri, Oct 23, 2015 at 12:07 PM, Ajay Garg <ajaygargnsit@gmail.com>
> wrote:
>
>> Any ideas, please?
>> To repeat, we are using the exact same cassandra-version on all 4 nodes
>> (2.1.10).
>>
>> On Fri, Oct 23, 2015 at 9:43 AM, Ajay Garg <ajaygargnsit@gmail.com>
>> wrote:
>>
>>> Hi Michael.
>>>
>>> Please find below the contents of cassandra.yaml for CAS11 (the files on
>>> the rest of the three nodes are also exactly the same, except the
>>> "initial_token" and "listen_address" fields) ::
>>>
>>> CAS11 ::
>>>
>>>
>>>
>>> What changes need to be made, so that whenever a downed server comes
>>> back up, the missing data comes back over to it?
>>>
>>> Thanks and Regards,
>>> Ajay
>>>
>>>
>>>
>>> On Fri, Oct 23, 2015 at 9:05 AM, Michael Shuler <michael@pbandjelly.org>
>>> wrote:
>>>
>>>> On 10/22/2015 10:14 PM, Ajay Garg wrote:
>>>>
>>>>> However, CAS11 refuses to come up now.
>>>>> Following is the error in /var/log/cassandra/system.log ::
>>>>>
>>>>>
>>>>> ################################################################
>>>>> ERROR [main] 2015-10-23 03:07:34,242 CassandraDaemon.java:391 - Fatal
>>>>> configuration error
>>>>> org.apache.cassandra.exceptions.ConfigurationException: Cannot change
>>>>> the number of tokens from 1 to 256
>>>>>
>>>>
>>>> Check your cassandra.yaml - this node has vnodes enabled in the
>>>> configuration when it did not, previously. Check all nodes. Something
>>>> changed. Mixed vnode/non-vnode clusters is bad juju.
>>>>
>>>> --
>>>> Kind regards,
>>>> Michael
>>>>
>>>
>>>
>>>
>>> --
>>> Regards,
>>> Ajay
>>>
>>
>>
>>
>> --
>> Regards,
>> Ajay
>>
>
>
>
> --
> Steve Robenalt
> Software Architect
> srobenalt@highwire.org <bzavon@highwire.org>
> (office/cell): 916-505-1785
>
> HighWire Press, Inc.
> 425 Broadway St, Redwood City, CA 94063
> www.highwire.org
>
> Technology for Scholarly Communication
>



-- 
Regards,
Ajay

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