It's advisable to set the RF to 3 regardless of the consistency level. If using RF=1, Read CL=LOCAL_ONE and a node goes down in the local DC, you will not be able to read data related to this node until it goes back up. For writes and CL=LOCAL_ONE, the write will fail (if it falls on the token ranges of the downed node).
On Tue, May 8, 2018 at 3:05 PM, Lucas Benevides <lu...@maurobenevides.com.br > wrote: > Yes, but remind that there is Write Consistency and Read Consistency. > To prevent the reads from reaching the other DC, you should set the Read > Consistency LOCAL_ONE. > As Hannu Kroger said, the LOCAL_ONE may be enough to you but maybe not if > you want to be sure that your data was written also in another DC. > > Lucas B. Dias > > > 2018-05-08 7:26 GMT-03:00 Hannu Kröger <hkro...@gmail.com>: > >> Writes are always replicated to all nodes (if they are online). >> >> LOCAL_ONE in writes just means that client will get an “OK” for the write >> only after at least node in local datacenter has acknowledged that the >> write is done. >> >> If all local replicas are offline, then the write will fail even if it >> gets written in your other DC. >> >> Hannu >> >> >> On 8 May 2018, at 13:24, Jakub Lida <jakub.l...@gmail.com> wrote: >> >> Hi, >> >> I want to add a new DC to an existing cluster (RF=1 per DC). >> Will setting consistency to LOCAL_ONE on all machines make it still >> replicate write requests sent to online DCs to all DCs (including the new >> one being rebuilt) and only isolate read requests from reaching the new DC? >> That is basically want I want to accomplish. >> >> Thanks in advance, Jakub >> >> >> >