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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: If one seed node crash, how can I add one seed node?
Date Wed, 08 Dec 2010 01:30:34 GMT
"Two seeds per datacenter" is my rule of thumb.

On Tue, Dec 7, 2010 at 3:07 PM, Eric Gilmore <eric@riptano.com> wrote:

> What would comprise a sane and reasonably balanced list?  Should there be a
> certain proportion of seeds per total nodes?  Any other considerations
> besides a) list must be identical on all nodes and b) you can't
> auto-bootstrap a seed node?
>
> I'm new to thinking about this setting, but it sounds like this discussion
> may be approaching some best-practice guidelines.
>
>
> On Tue, Dec 7, 2010 at 1:01 PM, Jonathan Ellis <jbellis@gmail.com> wrote:
>
>> The gossip-to-seed each round is to prevent cluster partitions, so if
>> you're following correct procedure and making every node's seed list
>> identical, then any potential new nodes gossiping to one of the old seeds
>> means it is still harmless for old nodes not to gossip to the new one until
>> the next restart.
>>
>>
>> On Tue, Dec 7, 2010 at 2:10 PM, Aaron Morton <aaron@thelastpickle.com>wrote:
>>
>>> Ryan,
>>> I've not checked with the code but the wiki docs for the Gossip Protocol
>>> say it makes use of the seed list.
>>> http://wiki.apache.org/cassandra/ArchitectureGossip
>>>
>>> During each gossip round a node will try to gossip to one seed node.
>>>
>>> Which made me think keeping the list sane and reasonably balanced was a
>>> good idea. Obviously would not matter too much on a small cluster though.
>>>
>>> Aaron
>>>
>>>
>>> On 08 Dec, 2010,at 07:16 AM, Ryan King <ryan@twitter.com> wrote:
>>>
>>> Note that there's not really anything special about the seed node and its
>>> all relative– the cluster doesn't necessarily have to agreed on who the
>>> seeds are.
>>>
>>> So, to bring up a new node to replace the old seed, just set the new
>>> node's seed to any existing node in the system. After that you can go back
>>> and make the setting consistent across the cluster.
>>>
>>> -ryan
>>>
>>> On Tue, Dec 7, 2010 at 7:01 AM, Nick Bailey <nick@riptano.com> wrote:
>>>
>>>> Yes, cassandra only reads the configuration when it starts up. However
>>>> seed nodes are only used when a node starts. After that they aren't needed.
>>>> There should be no reason to restart your cluster after adding a seed node
>>>> to  your cluster.
>>>>
>>>>
>>>>
>>>> On Tue, Dec 7, 2010 at 2:09 AM, aaron morton <aaron@thelastpickle.com>wrote:
>>>>
>>>>> You will need to restart the nodes for them to pickup changes in
>>>>> cassandra.yaml
>>>>>
>>>>>
>>>>> Aaron
>>>>>
>>>>>
>>>>> On 7 Dec 2010, at 16:32, lei liu wrote:
>>>>>
>>>>> Thanks Nick.
>>>>>
>>>>> After I add the new node as seed node in the configuration for all of
>>>>> my nodes, do I need to restart all of my nodes?
>>>>>
>>>>> 2010/12/7 Nick Bailey <nick@riptano.com>
>>>>>
>>>>>> The node can be set as a seed node at any time. It does not need
to be
>>>>>> a seed node when it joins the cluster. You should remove it as a
seed node,
>>>>>> set autobootstrap to true and let it join the cluster. Once it has
joined
>>>>>> the cluster you should add it as a seed node in the configuration
for all of
>>>>>> your nodes.
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Mon, Dec 6, 2010 at 9:59 AM, lei liu <liulei412@gmail.com>
wrote:
>>>>>>
>>>>>>> Thank Jonathan for your reply.
>>>>>>>
>>>>>>> How  can I bootstrap the node into cluster, I know if the node
is
>>>>>>> seed node, I can't set AutoBootstrap to true.
>>>>>>>
>>>>>>> 2010/12/6 Jonathan Ellis <jbellis@gmail.com>
>>>>>>>
>>>>>>>> set it as a seed _after_ bootstrapping it into the cluster.
>>>>>>>>
>>>>>>>>
>>>>>>>> On Mon, Dec 6, 2010 at t5:01 AM, lei liu <liulei412@gmail.com>
>>>>>>>> wrote:
>>>>>>>> > After one seed node crash, I want to add one node as
seed node, I
>>>>>>>> set
>>>>>>>> > auto_bootstrap to true, but the new node don't migrate
data from
>>>>>>>> other
>>>>>>>> > node s.
>>>>>>>> >
>>>>>>>> > How can I add one new seed node and let the node to
migrate data
>>>>>>>> from other
>>>>>>>> > nodes?
>>>>>>>> >
>>>>>>>> >
>>>>>>>> >
>>>>>>>> > Thanks,
>>>>>>>> >
>>>>>>>> > LiuLei
>>>>>>>> >
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> --
>>>>>>>> Jonathan Ellis
>>>>>>>> Project Chair, Apache Cassandra
>>>>>>>> co-founder of Riptano, the source for professional Cassandra
support
>>>>>>>> http://riptano.com
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>
>>
>>
>> --
>> Jonathan Ellis
>> Project Chair, Apache Cassandra
>> co-founder of Riptano, the source for professional Cassandra support
>> http://riptano.com
>>
>
>
>
> --
> *Eric Gilmore
> *
> Consulting Technical Writer
> Riptano, Inc.
> Ph: 510 684 9786  (cell)
>
>


-- 
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support
http://riptano.com

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