Hello Joshua Thank you very much for the replies. I will go through the tickets you sent to understand the process.
Regards, Pradeep On Mon, Aug 27, 2018 at 6:15 AM, rajasekhar kommineni <rajaco...@gmail.com> wrote: > Hi Pradeep, > > For changing the snitch you have decommission and add the node with new > switch and updated properties files. > > Thanks, > > > On Aug 26, 2018, at 2:15 PM, Joshua Galbraith <jgalbra...@newrelic.com. > INVALID> wrote: > > Pradeep, > > Here are some related tickets that may also be helpful in understanding > the current behavior of these options. > > * https://issues.apache.org/jira/browse/CASSANDRA-5897 > * https://issues.apache.org/jira/browse/CASSANDRA-9474 > * https://issues.apache.org/jira/browse/CASSANDRA-10243 > * https://issues.apache.org/jira/browse/CASSANDRA-10242 > > On Sun, Aug 26, 2018 at 1:20 PM, Joshua Galbraith <jgalbra...@newrelic.com > > wrote: > >> Pradeep, >> >> That being said, I haven't experimented with -Dcassandra.ignore_dc=true >> -Dcassandra.ignore_rack=true before. >> >> The description here may be helpful: >> https://github.com/apache/cassandra/blob/trunk/NEWS.txt#L685-L693 >> >> I would spin up a small test cluster with data you don't care about and >> verify that your above assumptions are correct there first. >> >> On Sun, Aug 26, 2018 at 1:09 PM, Joshua Galbraith < >> jgalbra...@newrelic.com> wrote: >> >>> Pradeep. >>> >>> Right, so from that documentation is sounds like you actually have to >>> stop all nodes in the cluster at once and bring them back up one at a time. >>> A rolling restart won't work here. >>> >>> On Sun, Aug 26, 2018 at 11:46 AM, Pradeep Chhetri <prad...@stashaway.com >>> > wrote: >>> >>>> Hi Joshua, >>>> >>>> Thank you for the reply. Sorry i forgot to mention that I already went >>>> through that documentation. There are few missing things regarding which I >>>> have few questions: >>>> >>>> 1) One thing which isn't mentioned there is that cassandra fails to >>>> restart when we change the datacenter name *or* rack name of a node. >>>> So whether should i first rolling restart cassandra with flag >>>> "-Dcassandra.ignore_dc=true -Dcassandra.ignore_rack=true", then run >>>> sequential repair and then cleanup and then rolling restart cassandra >>>> without that flag. >>>> >>>> 2) Should i not allow any read/write operation from applications during >>>> the time when sequential repair is running. >>>> >>>> Regards, >>>> Pradeep >>>> >>>> On Mon, Aug 27, 2018 at 12:19 AM, Joshua Galbraith < >>>> jgalbra...@newrelic.com.invalid> wrote: >>>> >>>>> Pradeep, it sounds like what you're proposing counts as a topology >>>>> change because you are changing the datacenter name and rack name. >>>>> >>>>> Please refer to the documentation here about what to do in that >>>>> situation: >>>>> https://docs.datastax.com/en/cassandra/3.0/cassandra/operati >>>>> ons/opsSwitchSnitch.html >>>>> >>>>> In particular: >>>>> >>>>> Simply altering the snitch and replication to move some nodes to a new >>>>>> datacenter will result in data being replicated incorrectly. >>>>> >>>>> >>>>> Topology changes may occur when the replicas are placed in different >>>>>> places by the new snitch. Specifically, the replication strategy places >>>>>> the >>>>>> replicas based on the information provided by the new snitch. >>>>> >>>>> >>>>> If the topology of the network has changed, but no datacenters are >>>>>> added: >>>>>> a. Shut down all the nodes, then restart them. >>>>>> b. Run a sequential repair and nodetool cleanup on each node. >>>>> >>>>> >>>>> On Sun, Aug 26, 2018 at 11:14 AM, Pradeep Chhetri < >>>>> prad...@stashaway.com> wrote: >>>>> >>>>>> Hello everyone, >>>>>> >>>>>> Since i didn't hear from anyone, just want to describe my question >>>>>> again: >>>>>> >>>>>> Am i correct in understanding that i need to do following steps to >>>>>> migrate data from SimpleSnitch to GPFS changing datacenter name and rack >>>>>> name to AWS region and Availability zone respectively >>>>>> >>>>>> 1) Update the rack and datacenter fields in >>>>>> cassandra-rackdc.properties file and rolling restart cassandra with this >>>>>> flag "-Dcassandra.ignore_dc=true -Dcassandra.ignore_rack=true" >>>>>> >>>>>> 2) Run nodetool repair --sequential and nodetool cleanup. >>>>>> >>>>>> 3) Rolling restart cassandra removing the flag >>>>>> "-Dcassandra.ignore_dc=true -Dcassandra.ignore_rack=true" >>>>>> >>>>>> Regards, >>>>>> Pradeep >>>>>> >>>>>> On Thu, Aug 23, 2018 at 10:53 PM, Pradeep Chhetri < >>>>>> prad...@stashaway.com> wrote: >>>>>> >>>>>>> Hello, >>>>>>> >>>>>>> I am currently running a 3.11.2 cluster in SimpleSnitch hence the >>>>>>> datacenter is datacenter1 and rack is rack1 for all nodes on AWS. I >>>>>>> want to >>>>>>> switch to GPFS by changing the rack name to the availability-zone name >>>>>>> and >>>>>>> datacenter name to region name. >>>>>>> >>>>>>> When I try to restart individual nodes by changing those values, it >>>>>>> failed to start throwing the error about dc and rack name mismatch but >>>>>>> gives me an option to set ignore_dc and ignore_rack to true to bypass >>>>>>> it. >>>>>>> >>>>>>> I am not sure if it is safe to set those two flags to true and if >>>>>>> there is any drawback now or in future when i add a new datacenter to >>>>>>> the >>>>>>> cluster. I went through the documentation on Switching Snitches but >>>>>>> didn't >>>>>>> get much explanation. >>>>>>> >>>>>>> Regards, >>>>>>> Pradeep >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>> >>>>> >>>>> -- >>>>> *Joshua Galbraith *| Lead Software Engineer | New Relic >>>>> >>>> >>>> >>> >>> >>> -- >>> *Joshua Galbraith *| Lead Software Engineer | New Relic >>> >> >> >> >> -- >> *Joshua Galbraith *| Lead Software Engineer | New Relic >> > > > > -- > *Joshua Galbraith *| Lead Software Engineer | New Relic > > >
