Also beware of "DC goes down" is not necessarily a total failure. It may be only a given client that doesn't see the DC, it may be that some hosts in one DC sees some hosts in the other DC and so on... The black/white "DC goes down" perception may lead to poor decisions on how to deal with failures.
Cheers Niclas On Thu, Apr 19, 2018 at 6:52 PM, Venkata Hari Krishna Nukala < n.v.harikrishna.apa...@gmail.com> wrote: > Hi, > > I am working on a C* cluster which is installed on two data centres. Our > app is in installed on those data centres and they serve life traffic all > the time. Keyspaces are configure with NetworkTopologyStrategy and we are > using LOCAL_QUORUM. Now I have got a case where stronger consistency is > required across DCs, so would like to switch to EACH_QUORUM. > > Suppose if one DC goes down, I would like to fallback to LOCAL_QUORUM so > that our app can continue serving requests and data can be eventually > consistent when it is up. > > Now the question is: how to detect if a DC is down programmatically at the > client so that I can switch the consistency level? > > Thanks! > -- Niclas Hedhman, Software Developer http://polygene.apache.org - New Energy for Java
