On Thu, Jul 11, 2019 at 5:04 PM Voytek Jarnot <voytek.jar...@gmail.com>
wrote:
> My google-fu is failing me this morning. I'm looking for any tips on
> splitting a 2 DC cluster into two separate clusters. I see a lot of docs
> about decomissioning a datacenter, but not much in the way of disconnecting
> datacenters into individual clusters, but keeping each one as-is data-wise
> (aside from replication factor, of course).
>
> Our setup is simple: two DCs (dc1 and dc2), two seed nodes (both in dc1;
> yes, I know not the recommended config), one keyspace (besides the system
> ones) replicated in both DCs. I'm trying to end up with two clusters with 1
> DC in each.
>
The first step that comes to my mind would be this:
cql in dc1=> ALTER KEYSPACE data WITH ... {'dc1': RF};
cql in dc2=> ALTER KEYSPACE data WITH ... {'dc2': RF};
Then you probably want to update seeds list of each DC to contain only
nodes from that local DC. The next step is tricky, but somehow it feels
that you will need to isolate then networks, so that nodes in DC1 see all
nodes from DC2 as DOWN and vice-versa, then assassinate the nodes from
remote DC.
Testing in a lab first is probably a good idea. ;-)
--
Alex
