If you're at 1 node (N=1) and RF=1 now, and you want to go N=3 RF=3, you ought to be able to increase RF to 3 before bootstrapping your new nodes, with no downtime and no loss of data (even temporary). Effective RF is min-bounded by N, so temporarily having RF > N ought to behave as RF = N.
If you're starting at N > RF and you want to increase RF, things get harrier if you can't afford temporary consistency issues. On Wed, Oct 7, 2015 at 10:58 AM Ajay Garg <ajaygargn...@gmail.com> wrote: > Hi Sean. > > Thanks for the reply. > > On Wed, Oct 7, 2015 at 10:13 PM, <sean_r_dur...@homedepot.com> wrote: > > How many nodes are you planning to add? > > I guess 2 more. > > > How many replicas do you want? > > 1 (original) + 2 (replicas). > That makes it a total of 3 copies of every row of data. > > > > > In general, there shouldn't be a problem adding nodes and then altering > the keyspace to change replication. > > Great !! > I guess > http://docs.datastax.com/en/cql/3.0/cql/cql_reference/alter_keyspace_r.html > will do the trick for changing schema-replication-details !! > > > > You will want to run repairs to stream the data to the new replicas. > > Hmm.. we'll be really grateful if you could point us to a suitable > link for the above step. > If there is a nice-utility, we would be perfectly set up to start our > fun-exercise, consisting of following steps :: > > a) > (As advised by you) Changing the schema, to allow a replication_factor of > 3. > > b) > (As advised by you) Duplicating the already-existing-data on the other 2 > nodes. > > c) > Thereafter, let Cassandra create a total of 3 copies for every row of > new-incoming-data. > > > Once again, thanks a ton for the help !! > > > Thanks and Regards, > Ajay > > > > You shouldn't need downtime or data migration -- this is the beauty of > > Cassandra. > > > > > > > > > > Sean Durity – Lead Cassandra Admin > > > > > ________________________________ > > > > The information in this Internet Email is confidential and may be > legally privileged. It is intended solely for the addressee. Access to this > Email by anyone else is unauthorized. If you are not the intended > recipient, any disclosure, copying, distribution or any action taken or > omitted to be taken in reliance on it, is prohibited and may be unlawful. > When addressed to our clients any opinions or advice contained in this > Email are subject to the terms and conditions expressed in any applicable > governing The Home Depot terms of business or client engagement letter. The > Home Depot disclaims all responsibility and liability for the accuracy and > content of this attachment and for any damages or losses arising from any > inaccuracies, errors, viruses, e.g., worms, trojan horses, etc., or other > items of a destructive nature, which may be contained in this attachment > and shall not be liable for direct, indirect, consequential or special > damages in connection with this e-mail message or its attachment. > > > > -- > Regards, > Ajay >
