cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From AJ ...@dude.podzone.net>
Subject Re: Docs: Token Selection
Date Wed, 15 Jun 2011 02:31:27 GMT
Yes, which means that the ranges overlap each other.

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

DC1
node 1 = 0      Range: (12, 16], (0, 0]
node 2 = 4      Range: (0, 4]

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

If this is OK, are there any drawbacks to this?



On 6/14/2011 6:10 PM, Vijay wrote:
> Yes... Thats right...  If you are trying to say the below...
>
> DC1
> Node1 Owns 50%
>
>     (Ranges 8..4 -> 8..5 & 8..5 -> 0)
>
> Node2 Owns 50%
>
>     (Ranges 0 -> 1 & 1 -> 8..4)
>
>
> DC2
> Node1 Owns 50%
>
>     (Ranges 8..5 -> 0 & 0 -> 1)
>
> Node2 Owns 50%
>
>     (Ranges 1 -> 8..4 & 8..4 -> 8..5)
>
>
> Regards,
> </VJ>
>
>
>
> On Tue, Jun 14, 2011 at 3:47 PM, AJ <aj@dude.podzone.net 
> <mailto:aj@dude.podzone.net>> wrote:
>
>     This http://wiki.apache.org/cassandra/Operations#Token_selection
>      says:
>
>     "With NetworkTopologyStrategy, you should calculate the tokens the
>     nodes in each DC independantly."
>
>     and gives the example:
>
>     DC1
>     node 1 = 0
>     node 2 = 85070591730234615865843651857942052864
>
>     DC2
>     node 3 = 1
>     node 4 = 85070591730234615865843651857942052865
>
>
>     So, according to the above, the token ranges would be (abbreviated
>     nums):
>
>     DC1
>     node 1 = 0      Range: (8..4, 16], (0, 0]
>     node 2 = 8..4   Range: (0, 8..4]
>
>     DC2
>     node 3 = 1      Range: (8..5, 16], (0, 1]
>     node 4 = 8..5   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?  Was this design
>     to help keep data somewhat localized if that was important, such
>     as a geographically dispersed DC?
>
>     Thanks!
>
>


Mime
View raw message