> Is the above understanding correct ?
yes, sorry.
Cheers
-
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com
On 13/07/2012, at 4:24 PM, prasenjit mukherjee wrote:
> On Fri, Jul 13, 2012 at 4:04 AM, aaron morton wrote:
>> The logic is here
>> https://gi
On Fri, Jul 13, 2012 at 4:04 AM, aaron morton wrote:
> The logic is here
> https://github.com/apache/cassandra/blob/cassandra-1.1/src/java/org/apache/cassandra/locator/NetworkTopologyStrategy.java#L78
Thanks Aaron for pointing to the code.
>
> a. n>r : I am assuming, have 1 replica in each rack.
> WIll it also use the
> snitch/strategy info to find next 'R' replicas 'closest' to
> coordinator-node ?
yes.
> 2. In a single DC ( with n racks and r replicas ) what algorithm
The logic is here
https://github.com/apache/cassandra/blob/cassandra-1.1/src/java/org/apache/cassandra/locator/NetworkT
Thanks. Some follow up questions :
1. How do the reads use strategy/snitch information ? I am assuming
the reads can go to any of the replicas. WIll it also use the
snitch/strategy info to find next 'R' replicas 'closest' to
coordinator-node ?
2. In a single DC ( with n racks and r replicas ) wh
I highly recommend specifying the same rack for all nodes (using
cassandra-topology.properties) unless you really have a good reason not too
(and you probably don't). The way that replicas are chosen when multiple
racks are in play can be fairly confusing and lead to a data imbalance if
you don't
> As far as I know there isn't any way to use the rack name in the
> strategy_options for a keyspace. You
> might want to look at the code to dig into that, perhaps.
Aha, I was wondering if I could do that as well ( specify rack options ) :)
Thanks for the pointer, I will dig into the code.
-Th
Using PropertyFileSnitch you can fine tune the topology of the cluster.
What you tell Cassandra about your "DC" and "rack" doesn't have to match how
they are in real life. You can create virtual DCs for Cassandra and even treat
each node as a separate rack.
For example, in cassandra-topology.p
