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Posted to user@cassandra.apache.org by Roshan <co...@gmail.com> on 2012/02/13 02:42:35 UTC
Multiple data center nodetool ring output display 0% owns
Hi
I have deployed Cassandra 1.0.6 to a 2 data center and one data center (DC1)
having one node and the other data center (DC2) having two nodes. But when I
do a nodetool ring using one IP, the output says 0% owns of DC1 node. Please
see the output below.
# sh nodetool -h 10.XXX.XXX.XX ring
Address DC Rack Status State Load Owns
Token
85070591730234615865843651857942052864
XXX.XXX.XXX.XXX DC2 RAC1 Up Normal 83.89 KB
50.00% 0
YYY.YYY.YY.YYY DC1 RAC1 Up Normal 71.4 KB 0.00%
1
ZZ.ZZZ.ZZZ.ZZ DC2 RAC1 Up Normal 65.94 KB
50.00% 85070591730234615865843651857942052864
Could someone explain this behavior.
--
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Re: Multiple data center nodetool ring output display 0% owns
Posted by Peter Schuller <pe...@infidyne.com>.
> There was a thread on this a couple days ago -- short answer, the 'owns %' column is effectively incorrect when you're using multiple DCs. If you had all 3 servers in 1 DC, since server YYY has token 1 and server XXX has token 0, then server XXX would truly 'own' 0% (actually, 1/(2^128) :) ), and depending on your replication factor might have no data (if replication were 1).
It's also incorrect for rack awareness if your topology is such that
the rack awareness changes ownership (see
https://issues.apache.org/jira/browse/CASSANDRA-3810).
--
/ Peter Schuller (@scode, http://worldmodscode.wordpress.com)
Re: Multiple data center nodetool ring output display 0% owns
Posted by David Schairer <ds...@humbaba.net>.
There was a thread on this a couple days ago -- short answer, the 'owns %' column is effectively incorrect when you're using multiple DCs. If you had all 3 servers in 1 DC, since server YYY has token 1 and server XXX has token 0, then server XXX would truly 'own' 0% (actually, 1/(2^128) :) ), and depending on your replication factor might have no data (if replication were 1).
But two data centers is effectively like two rings - since the two nodes in DC2 are token-balanced, you'd see even distribution between them, and DC1 has only one server, so that would be even as well (assuming you replicate to both sites).
--DRS
On Feb 12, 2012, at 5:42 PM, Roshan wrote:
> Hi
>
> I have deployed Cassandra 1.0.6 to a 2 data center and one data center (DC1)
> having one node and the other data center (DC2) having two nodes. But when I
> do a nodetool ring using one IP, the output says 0% owns of DC1 node. Please
> see the output below.
>
> # sh nodetool -h 10.XXX.XXX.XX ring
> Address DC Rack Status State Load Owns
> Token
>
> 85070591730234615865843651857942052864
> XXX.XXX.XXX.XXX DC2 RAC1 Up Normal 83.89 KB
> 50.00% 0
> YYY.YYY.YY.YYY DC1 RAC1 Up Normal 71.4 KB 0.00%
> 1
> ZZ.ZZZ.ZZZ.ZZ DC2 RAC1 Up Normal 65.94 KB
> 50.00% 85070591730234615865843651857942052864
>
> Could someone explain this behavior.
>
> --
> View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Multiple-data-center-nodetool-ring-output-display-0-owns-tp7279122p7279122.html
> Sent from the cassandra-user@incubator.apache.org mailing list archive at Nabble.com.