> You are advising me to test it, what would be a good way of testing it (I can > use AWS EC2 instances if needed) ? If you are only using one Available Zone per region then you have only one rack per DC and the NetworkTopologyStrategy will do the right thing.
> Why ? I mean we have maybe only 5% of our customers on the us-east zone, what > in C* require to have the same number of node on each DC ? Because you are going to replicate your data 3 times in each DC so that each DC can operate with a LOCAL_QUOURM. > What is better on adding nodes with no data and then rebuild them compared to > using the auto_bootstrap ? nodetool rebuild is designed to handle pulling data from another dc, so you can use it when the local DC does not contain data. i.e. you do not want a node in the new DC bootstrapping from other nodes in the new DC, they have no data. > Any doc on this ? I am not aware of all the possibilities. Why is this the > best method according to you ? http://wiki.apache.org/cassandra/Operations?highlight=%28token%29#Token_selection http://www.datastax.com/docs/1.2/initialize/token_generation Cause it's easier to understand than interleaving the nodes and works with 2+ DC's. > What is the point of this ? http://wiki.apache.org/cassandra/FAQ#seed > I didn't thought this change would be that tricky, thank you guys for these > warnings and your help ;) Yup, this is a lot of work. Cheers ----------------- Aaron Morton Freelance Cassandra Consultant New Zealand @aaronmorton http://www.thelastpickle.com On 23/04/2013, at 7:26 PM, Alain RODRIGUEZ <arodr...@gmail.com> wrote: > Hi,these advice are very welcome. > > @Dane, about the rack awareness, we use only one rack per DC, so I guess > using EC2MultiRegionSnitch will do just fine and it doesn't need any > configuration. Does it seem right to you. If we are someday interested on > multi racks I will make sure to use them properly. Thank you for this insight > anyway. You are advising me to test it, what would be a good way of testing > it (I can use AWS EC2 instances if needed) ? > > @Aaron > > "I recommend using the same number of nodes in both DC's." > > Why ? I mean we have maybe only 5% of our customers on the us-east zone, what > in C* require to have the same number of node on each DC ? > > "Add the nodes (I recommend 6) with auto_bootstrap: false added to the yaml. > update the keyspace replication strategy to add rf:3 for the new DC. > Use nodetool rebuild on the new nodes to rebuild them from the us-west DC. " > > What is better on adding nodes with no data and then rebuild them compared to > using the auto_bootstrap ? > > "I prefer to use the offset method. Take the 6 tokens from your us-west DC > and add 100 to them for the new dc. " > > Any doc on this ? I am not aware of all the possibilities. Why is this the > best method according to you ? > > About seeds => "Yes. Have 3 from each." > > What is the point of this ? > > I didn't thought this change would be that tricky, thank you guys for these > warnings and your help ;) > > Alain > > > 2013/4/23 Dane Miller <d...@optimalsocial.com> > On Thu, Apr 18, 2013 at 7:41 AM, Alain RODRIGUEZ <arodr...@gmail.com> wrote: > > I am wondering about the process to grow from one data center to a few of > > them. First thing is we use EC2Snitch for now. So I guess we have to switch > > to Ec2MultiRegionSnitch. > > > > c/ I am using the SimpleStrategy. Is it worth it/mandatory to change this > > strategy when using multiple DC ? > > I suggest you thoroughly read the datastax documentation on cassandra > replication. The change you are planning is big - make sure to try it > in a test environment first. Also, you might find you don't really > need Cassandra's rack aware feature, and can operate using > (Gossiping)PropertyFileSnitch. The rack feature is listed as an > "anti-pattern" here: > http://www.datastax.com/docs/1.2/cluster_architecture/anti_patterns > > Here are some recent discussions on this list: > http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/migrating-from-SimpleStrategy-to-NetworkTopologyStrategy-tp7586272.html > http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/migrating-from-SimpleStrategy-to-NetworkTopologyStrategy-tp7481090.html > > Dane >
