consistency against rebuild a new DC

[Peng Xiao <25...@qq.com>]

Hi there,


We know that we need to run repair regularly to make data consistency,suppose we have DC1 & DC2,
if we add a new DC3 and rebuild from DC1,can we suppose the DC3 is consistency with DC1 at least at the time when DC3 is rebuild successfully?


Thanks,
Peng Xiao,

Re: consistency against rebuild a new DC

[kurt greaves <ku...@instaclustr.com>]

No. Rebuilds don't keep consistency as they aren't smart enough to stream
from a specific replica, this all replicas for a rebuild can stream from a
single replica. You need to repair after rebuilding.

If you're using NTS with #racks >= RF you can stream consistently. if this
patch gets in https://issues.apache.org/jira/browse/CASSANDRA-13841

you could also achieve the same atm if you are using single tokens.

On 27 Nov. 2017 20:33, "Peng Xiao" <25...@qq.com> wrote:

> Hi there,
>
> We know that we need to run repair regularly to make data
> consistency,suppose we have DC1 & DC2,
> if we add a new DC3 and rebuild from DC1,can we suppose the DC3 is
> consistency with DC1 at least at the time when DC3 is rebuild successfully?
>
> Thanks,
> Peng Xiao,
>