Thank you. For 0.7 are the steps similar?
On Jul 27, 2011, at 19:56, Jonathan Ellis <jbel...@gmail.com> wrote: > As you know, with 0.6 adding a datacenter is not as easy as 0.7 with > NetworkTopologyStrategy. With 0.6 there is a right way that will work > with some manual effort, and a wrong way that can cause you major pain > and grief. > > The right way: > - Switch to a DC-aware snitch but leave your cluster on RUS to start with. > - Bootstrap the 2nd datacenter nodes (halfway) in between your 1st > datacenter tokens, so your ring alternates DC1 DC2 DC1 DC2 etc. Do > this one at a time for minimum disruption. You should have equal node > counts in each DC because RAS will keep data in each DC about equal. > - Switch the cluster to RAS > - Start repair. You will need to run repair on each node. In 0.6 you > should only run repair against one node at a time. > - While repair is going on, you need to do reads at at least CL.QUORUM > or data may appear to be missing, since it's not yet in all the places > the new strategy will look. (But by alternating DC around the ring, 2 > of the 3 replicas are guaranteed to be the same for both RUS and RAS.) > > The wrong way: > - Switch to RAS, then start adding nodes in the new DC. As soon as > you add the first node in DC2, RAS will try to replicate ALL the rows > in DC1 to it. Usually this overwhelms the DC2 node and it dies a > fiery death. > > On Wed, Jul 27, 2011 at 7:44 PM, Ashley Martens <amart...@ngmoco.com> wrote: >> I have a current 0.6.x cluster in a single datacenter with RackUnaware and >> am looking to expand into a second data center. I know I need to change to >> RackAwareStrategy however, I'm not sure what will happen to my data when I >> restart the nodes in the current cluster before I even add the new DC. Will >> the data need to move based on the rack each node is in or will it stay on >> the node it is currently on? Also, when I start adding nodes in the new DC >> to the cluster should they come in one at a time, like bootstrap, or should >> I light up several at the same time to distribute the data? >> >> For reference I have 19 nodes in my cluster. >> >> Thanks. >> > > > > -- > Jonathan Ellis > Project Chair, Apache Cassandra > co-founder of DataStax, the source for professional Cassandra support > http://www.datastax.com
