You are right about the automatic fallback to ONE. Its quite possible, if 2
nodes die for some reason I will have the same problem. So probably the right
thing to do would be to read/write at ONE only when we lose a DC by changing
some manual configuration. Since we shouldn't be losing DCs
@cassandra.apache.org
Subject: Re: Cassandra 2 DC deployment
When the down data center comes back up, the Quorum reads will result in a
read-repair, so you will get valid data. Besides that, hinted handoff will
take care of getting data replicated to a previously down node.
*Eventually* though
Hi experts,
We are planning to deploy Cassandra in 2 datacenters. Let assume there
are 3 nodes, RF=3, 2 nodes in 1 DC and 1 node in 2nd DC. Under normal
operations, we would read and write at QUORUM. What we want to do though is
if we lose a datacenter which has 2 nodes, DC1 in this case, we
When the down data center comes back up, the Quorum reads will result in a
read-repair, so you will get valid data. Besides that, hinted handoff will
take care of getting data replicated to a previously down node.
You're example is a little unrealistic because you could theoretically have a
I think this is reasonable assuming you have enough backhaul to perform
reads across DC if read requests hit DC2 (with one copy of data) or one
replica from DC1 is down.
Moreover, since you clearly stated that you would prefer availability over
consistency, you should be prepared for stale reads
When the down data center comes back up, the Quorum reads will result in a
read-repair, so you will get valid data. Besides that, hinted handoff will
take care of getting data replicated to a previously down node.
*Eventually* though, but yes. I.e., there would be no expectation to
