See the bug report, implementations of IPartitioner.describeOwnership() Cheers
----------------- Aaron Morton Freelance Cassandra Developer @aaronmorton http://www.thelastpickle.com On 18/08/2011, at 2:58 AM, Oleg Tsvinev wrote: > Aaron, > > Can you point to a line in Cassandra sources where you believe it does > not understand the "multi ring" approach? > I'm not sure about Cassandra team but Hector team likes pull requests > with patches. > Anyways, I believe I should run a test to see if data is indeed > replicated between datacenters. > > And I voted on the issue. > > On Wed, Aug 17, 2011 at 2:20 AM, aaron morton <aa...@thelastpickle.com> wrote: >> >> The calculation for ownership does not understand the "multi ring" approach >> to assigning tokens. I've created >> https://issues.apache.org/jira/browse/CASSANDRA-3047 for you. >> Otherwise your tokens look good to me. >> Cheers >> ----------------- >> Aaron Morton >> Freelance Cassandra Developer >> @aaronmorton >> http://www.thelastpickle.com >> On 17/08/2011, at 9:19 AM, Oleg Tsvinev wrote: >> >> Hi all, >> >> I followed instructions here: >> http://wiki.apache.org/cassandra/Operations#Token_selection >> to create a Cassandra cluster spanning two datacenters. Now I see that >> nodes belonging to DC2 datacenter own 0% of the ring. I would expect >> them to own 50%. >> >> Does anyone have an idea what's going on here? >> >> root@casper02:~# nodetool -h 10.4.64.63 ring >> Address DC Rack Status State Load >> Owns Token >> >> 85070591730234615865843651857942052865 >> 10.4.64.63 DC1 RAC1 Up Normal 36.19 MB >> 50.00% 0 >> 10.4.65.55 DC2 RAC1 Up Normal 36.21 MB >> 0.00% 1 >> 10.4.65.73 DC1 RAC1 Up Normal 530.12 KB >> 50.00% 85070591730234615865843651857942052864 >> 10.4.64.166 DC2 RAC1 Up Normal 525.68 KB >> 0.00% 85070591730234615865843651857942052865 >> >> Thank you, >> Oleg >> >> ------------- >> >> On Mon, Aug 15, 2011 at 1:39 PM, Oleg Tsvinev <oleg.tsvi...@gmail.com> wrote: >> >> Hi all, >> >> I have a question that documentation has not clear answer for. I have >> >> the following requirements: >> >> 1. Synchronously store data in datacenter DC1 on 2+ nodes >> >> 2. Asynchronously replicate the same data to DC2 and store it on 2+ >> >> nodes to act as a hot standby >> >> Now, I have configured keyspaces with o.a.c.l.NetworkTopologyStrategy >> >> with strategy_options=[{DC1:2, DC2:2}] and use LOCAL_QUORUM >> >> consistency level, following documentation here: >> >> http://www.datastax.com/docs/0.8/operations/datacenter >> >> Now, how do I assign initial tokens? If I have, say 6 nodes total, 3 >> >> in DC1 and 3 in DC2, and create a ring as if all 6 nodes share the >> >> total 2^128 space equally. >> >> Now say node N1:DC2 has key K and is in remote datacenter (for an app >> >> in DC1). Wouldn't Cassandra always forward K to the DC2 node N1 thus >> >> turning asynchronous writes into synchronous ones? Performance impact >> >> will be huge as the latency between DC1 and DC2 is significant. >> >> I hope there's an answer and I'm just missing something. My case falls >> >> under Disaster Recovery in >> >> http://www.datastax.com/docs/0.8/operations/datacenter but I don't see >> >> how Cassandra will support my use case. >> >> I appreciate any help on this. >> >> Thank you, >> >> Oleg >> >>
