You need to make sure your clients are reading using LOCAL_* settings so
that they don't try to get data from the other data center. But you
shouldn't get errors while replication_factor is 0. Once you change the
replication factor to 4, you should get missing data if you are using
LOCAL_* for reading.
What version are you using?
See the IRC logs at the begining of this JIRA discussion thread for some
info:
https://issues.apache.org/jira/browse/CASSANDRA-3483
But you should be able to:
1. Set dc2:0 in the replication_factor.
2. Set bootstrap to false on the new nodes.
2. Start all of the new nodes.
3. Change replication_factor to dc2:4
4. run repair on the nodes in dc2.
Once the repairs finish you should be able to start using DC2. You are
still going to need a bunch of extra space because the repair is going
to get you a couple copies of the data.
Once 1.1 comes out it will have new nodetool commands for making this a
little nicer per CASSANDRA-3483
-Jeremiah
On 03/05/2012 09:42 AM, David Koblas wrote:
Everything that I've read about data centers focuses on setting things
up at the beginning of time.
I've the the following situation:
10 machines in a datacenter (DC1), with replication factor of 2.
I want to set up a second data center (DC2) with the following
configuration:
20 machines with a replication factor of 4
What I've found is that if I initially start adding things, the first
machine to join the network attempts to replicate all of the data from
DC1 and fills up it's disk drive. I've played with setting the
storage_options to have a replication factor of 0, then I can bring up
all 20 machines in DC2 but then start getting a huge number of read
errors from read on DC1.
Is there a simple cookbook on how to add a second DC? I'm currently
trying to set the replication factor to 1 and do a repair, but that
doesn't feel like the right approach.
Thanks,
