Re: Question about local reads with multiple data centers

[Chris Burroughs <ch...@gmail.com>]

On 01/29/2014 08:07 PM, Donald Smith wrote:
> My question: will the read process try to read first locally from the datacenter DC2 I specified in its connection string?     I presume so.  (I doubt that it uses the client's IP address to decide which datacenter is closer. And I am unaware of another way to tell it to read locally.)
>

 From the rest if this thread it looks like you were asking about how 
the client selected a Cassandra node to act as a coordinator.  Note 
however that if you are using a DC oblivious CL (ONE, QUORUM) then that 
Cassandra coordinator may send requests to the remote data center.


> Also, will read repair happen between datacenters automatically ("read_repair_chance=0.100000")?  Or does that only happen within a single data center?

Yes read_repair_chance is global.  There is a separate dc_local repair 
chance if you want to make local reap repairs more common.