Correction.... "The problem in the above approach is you have 2 nodes between 12 to 4 in DC1 but from 4 to 12 you just have 1"
should be "The problem in the above approach is you have 1 node between 0-4 (25%) and and one node covering the rest which is 4-16, 0-0 (75%)" Regards, </VJ> On Wed, Jun 15, 2011 at 11:10 AM, Vijay <vijay2...@gmail.com> wrote: > The problem in the above approach is you have 2 nodes between 12 to 4 in > DC1 but from 4 to 12 you just have 1.... (Which will cause uneven > distribution of data the node) > It is easier to think of the DCs 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 <a...@dude.podzone.net> wrote: > >> 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 <a...@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! >>> >> >> >> >
