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Subject: Re: EC2 node adding trouble
Date: Wed, 25 May 2011 08:50:07 +0200
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On 24 May 2011, at 23:58, Sameer Farooqui wrote:

> Even with AutoBootstrap it is recommended that you always specify the =
InitialToken on the new node because the picking of an initial token =
will almost certainly result in an unbalanced ring.
>=20
> Right now, I'm afraid that if you simply copied the YAML file from one =
of the two nodes to the 3rd node, then the 3rd node has an incorrect =
initial_token setting (it may be conflicting with node 1 or 2's range).=20=

>=20
> Some info about how to choose tokens:
> http://wiki.apache.org/cassandra/Operations#Token_selection
> =
http://journal.paul.querna.org/articles/2010/09/24/cassandra-token-selecti=
on/
>=20
> So, once you know what token each of the 3 nodes should have, shut =
down the first two nodes, change their tokens and add the correct token =
to the 3rd node (in the YAML file).

At the moment I'm not bothered about balance - just having it work at =
all would be good! initial_token is currently blank (i.e. self-defining =
according to the docs) on all nodes - I can see why that might cause =
balance issues, but I don't see that it would prevent it working as =
there should not be a token clash. If there was a token clash, wouldn't =
it throw an error saying so?

That second article, while wonderfully practical and informative, =
suggests that cassandra is really not suited to rapid scaling up or down =
- i.e. adding or removing nodes is neither quick nor painless, e.g. =
scaling from 5 to 20 nodes and back is something that might happen over =
weeks rather than minutes. Maybe cassandra just isn't the right tool for =
the job in this case?

Marcus=

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<html><head></head><body style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space; =
"><div><div>On 24 May 2011, at 23:58, Sameer Farooqui wrote:</div><br =
class=3D"Apple-interchange-newline"><blockquote type=3D"cite"><span =
class=3D"Apple-style-span" style=3D"border-collapse: separate; =
font-family: Helvetica; font-style: normal; font-variant: normal; =
font-weight: normal; letter-spacing: normal; line-height: normal; =
orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; =
widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; =
-webkit-border-vertical-spacing: 0px; =
-webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: =
auto; -webkit-text-stroke-width: 0px; font-size: medium; ">Even =
with&nbsp;AutoBootstrap&nbsp;it is recommended that you always specify =
the&nbsp;InitialToken on the new node because the picking of an initial =
token will almost certainly result in an unbalanced =
ring.<div><br></div><div>Right now, I'm afraid that if you simply copied =
the YAML file from one of the two nodes to the 3rd node, then the 3rd =
node has an incorrect initial_token setting (it may be conflicting with =
node 1 or 2's range).&nbsp;</div><div><br></div><div>Some info about how =
to choose tokens:</div><div><a =
href=3D"http://wiki.apache.org/cassandra/Operations#Token_selection">http:=
//wiki.apache.org/cassandra/Operations#Token_selection</a></div><div><a =
href=3D"http://wiki.apache.org/cassandra/Operations#Token_selection"></a><=
a =
href=3D"http://journal.paul.querna.org/articles/2010/09/24/cassandra-token=
-selection/">http://journal.paul.querna.org/articles/2010/09/24/cassandra-=
token-selection/</a><br><div><br></div><div>So, once you know what token =
each of the 3 nodes should have, shut down the first two nodes, change =
their tokens and add the correct token to the 3rd node (in the YAML =
file).</div></div></span></blockquote></div><br><div>At the moment I'm =
not bothered about balance - just having it work at all would be good! =
initial_token is currently blank (i.e. self-defining according to the =
docs) on all nodes - I can see why that might cause balance issues, but =
I don't see that it would prevent it working as there should not be a =
token clash. If there was a token clash, wouldn't it throw an error =
saying so?</div><div><br></div><div>That second article, while =
wonderfully practical and informative, suggests that cassandra is really =
not suited to rapid scaling up or down - i.e. adding or removing nodes =
is neither quick nor painless, e.g. scaling from 5 to 20 nodes and back =
is something that might happen over weeks rather than minutes. Maybe =
cassandra just isn't the right tool for the job in this =
case?</div><div><br></div><div>Marcus</div></body></html>=

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