Rega= rds,
</VJ>

On Wed, Jun 15, 2011 at 11:10 AM, Vijay = <vijay2win@gmai= l.com> wrote:

The problem in the above=C2=A0approach=C2=A0is you have 2 nodes between 12 = to 4 in DC1 but from 4 to 12 =C2=A0you just have 1.... (Which will cause un= even distribution of data the node)
It is easier to think of the D= Cs as ring and split equally and interleave them together....

DC1 Node 1 : token 0
DC1 Node 2 : token 8..

DC2 Node 1 : token 4..
DC2 Node 1 : token= 12..

Regards,
</VJ>

On Tue, Jun 14, 2011 at 7:31 PM, AJ <= aj@dude.podzone.net> wrote:
=20 =20 =20
Yes, which means that the ranges overlap each other.=C2=A0

Is this just a convention, or is it technically required when using NetworkTopologyStrategy?=C2=A0 Would it be acceptable to split the rang= es into quarters by ignoring the data centers, such as:

DC1
node 1 =3D 0 =C2=A0 =C2=A0 =C2=A0Range: (12, 16], (0, 0]
node 2 =3D 4 =C2=A0=C2=A0=C2=A0=C2=A0 Range: (0, 4]

DC2
node 3 =3D 8 =C2=A0 =C2=A0=C2=A0 Range: (4, 8]
node 4 =3D 12 =C2=A0 Range: (8, 12]

If this is OK, are there any drawbacks to this?=C2=A0

On 6/14/2011 6:10 PM, Vijay wrote:
Yes... Thats right... =C2=A0If you are trying= to say the below...

DC1

=20
Node1 Owns 50%=C2=A0

(Ranges=C2=A08..4 -> 8..5 &=C2=A08..5 -> 0)

Node2 Owns 50%=C2=A0

(Ranges 0 -> 1 & 1 -> 8..4)

DC2

=20

Node1 Owns 50%=C2=A0

(Ranges 8..5 -> 0 & 0 -> 1)

=20
=20
Node2 Owns 50%=C2=A0

(Ranges 1 -> 8..4 & 8..4 -> 8..5)

Regards,
</VJ>

On Tue, Jun 14, 2011 at 3:47 PM, AJ <aj@dude.podzone.net> wrote:

This http://wiki.apache.org/cassandra/Operatio= ns#Token_selection =C2=A0says:

"With NetworkTopologyStrategy, you should calculate the tokens the nodes in each DC independantly."

and gives the example:

DC1
node 1 =3D 0
node 2 =3D 85070591730234615865843651857942052864

DC2
node 3 =3D 1
node 4 =3D 85070591730234615865843651857942052865

So, according to the above, the token ranges would be (abbreviated nums):

DC1
node 1 =3D 0 =C2=A0 =C2=A0 =C2=A0Range: (8..4, 16], (0, 0] node 2 =3D 8..4 =C2=A0 Range: (0, 8..4]

DC2
node 3 =3D 1 =C2=A0 =C2=A0 =C2=A0Range: (8..5, 16], (0, 1] node 4 =3D 8..5 =C2=A0 Range: (1, 8..5]

If the above is correct, then I would be surprised as this paragraph is the only place were one would discover this and may be easy to miss... unless there's a doc buried somewhere in plain view that I missed.

So, have I interpreted this paragraph correctly? =C2=A0Was th= is design to help keep data somewhat localized if that was important, such as a geographically dispersed DC?

Thanks!