Re: Decommission datacenter - repair?
Ah, that explains things. Thanks! On Fri, Jun 5, 2015 at 10:59 PM, Robert Coli rc...@eventbrite.com wrote: On Fri, Jun 5, 2015 at 5:15 AM, Jens Rantil jens.ran...@tink.se wrote: Datastax's documentation on Decommissioning a data center http://docs.datastax.com/en/cassandra/2.0/cassandra/operations/ops_decomission_dc_t.html tells me to run a full repair and then decommission each node. Isn't decommissioning going to hand over all data anyway? Then why is the repair necessary? In step 3 of those instructions you reduce the number of replicas in the departing DC to 0. The departing DC no longer owns ranges at this point, and no longer is responsible for replicas. It therefore does no streaming (except maybe hints?) when you decommission nodes. =Rob -- Jens Rantil Backend engineer Tink AB Email: jens.ran...@tink.se Phone: +46 708 84 18 32 Web: www.tink.se Facebook https://www.facebook.com/#!/tink.se Linkedin http://www.linkedin.com/company/2735919?trk=vsrp_companies_res_phototrkInfo=VSRPsearchId%3A1057023381369207406670%2CVSRPtargetId%3A2735919%2CVSRPcmpt%3Aprimary Twitter https://twitter.com/tink
Decommission datacenter - repair?
Hi, I asked this on IRC earlier today, but didn't get any response; Datastax's documentation on Decommissioning a data center http://docs.datastax.com/en/cassandra/2.0/cassandra/operations/ops_decomission_dc_t.html tells me to run a full repair and then decommission each node. Isn't decommissioning going to hand over all data anyway? Then why is the repair necessary? Cheers, Jens -- Jens Rantil Backend engineer Tink AB Email: jens.ran...@tink.se Phone: +46 708 84 18 32 Web: www.tink.se Facebook https://www.facebook.com/#!/tink.se Linkedin http://www.linkedin.com/company/2735919?trk=vsrp_companies_res_phototrkInfo=VSRPsearchId%3A1057023381369207406670%2CVSRPtargetId%3A2735919%2CVSRPcmpt%3Aprimary Twitter https://twitter.com/tink
Re: Decommission datacenter - repair?
Hi Kiran, So, am I understanding you correctly that a decommissioning node only will hand over its data to a single node? If it would hand it over to all other replica nodes, I see that essentially as an implicit repair. Am I wrong? Thanks, Jens On Fri, Jun 5, 2015 at 2:27 PM, Kiran mk coolkiran2...@gmail.com wrote: Hi Jens, If you decommission a data center, The data residing in the Data Center which you are planning for decommission has to be balanced to the nodes of the other data center satisfying RF. Hence Repair is required. Best Regards, Kiran.M.K. On Fri, Jun 5, 2015 at 5:45 PM, Jens Rantil jens.ran...@tink.se wrote: Hi, I asked this on IRC earlier today, but didn't get any response; Datastax's documentation on Decommissioning a data center http://docs.datastax.com/en/cassandra/2.0/cassandra/operations/ops_decomission_dc_t.html tells me to run a full repair and then decommission each node. Isn't decommissioning going to hand over all data anyway? Then why is the repair necessary? Cheers, Jens -- Jens Rantil Backend engineer Tink AB Email: jens.ran...@tink.se Phone: +46 708 84 18 32 Web: www.tink.se Facebook https://www.facebook.com/#!/tink.se Linkedin http://www.linkedin.com/company/2735919?trk=vsrp_companies_res_phototrkInfo=VSRPsearchId%3A1057023381369207406670%2CVSRPtargetId%3A2735919%2CVSRPcmpt%3Aprimary Twitter https://twitter.com/tink -- Best Regards, Kiran.M.K. -- Jens Rantil Backend engineer Tink AB Email: jens.ran...@tink.se Phone: +46 708 84 18 32 Web: www.tink.se Facebook https://www.facebook.com/#!/tink.se Linkedin http://www.linkedin.com/company/2735919?trk=vsrp_companies_res_phototrkInfo=VSRPsearchId%3A1057023381369207406670%2CVSRPtargetId%3A2735919%2CVSRPcmpt%3Aprimary Twitter https://twitter.com/tink
Re: Decommission datacenter - repair?
Hi Jens, If you decommission a data center, The data residing in the Data Center which you are planning for decommission has to be balanced to the nodes of the other data center satisfying RF. Hence Repair is required. Best Regards, Kiran.M.K. On Fri, Jun 5, 2015 at 5:45 PM, Jens Rantil jens.ran...@tink.se wrote: Hi, I asked this on IRC earlier today, but didn't get any response; Datastax's documentation on Decommissioning a data center http://docs.datastax.com/en/cassandra/2.0/cassandra/operations/ops_decomission_dc_t.html tells me to run a full repair and then decommission each node. Isn't decommissioning going to hand over all data anyway? Then why is the repair necessary? Cheers, Jens -- Jens Rantil Backend engineer Tink AB Email: jens.ran...@tink.se Phone: +46 708 84 18 32 Web: www.tink.se Facebook https://www.facebook.com/#!/tink.se Linkedin http://www.linkedin.com/company/2735919?trk=vsrp_companies_res_phototrkInfo=VSRPsearchId%3A1057023381369207406670%2CVSRPtargetId%3A2735919%2CVSRPcmpt%3Aprimary Twitter https://twitter.com/tink -- Best Regards, Kiran.M.K.
Re: Decommission datacenter - repair?
On Fri, Jun 5, 2015 at 5:15 AM, Jens Rantil jens.ran...@tink.se wrote: Datastax's documentation on Decommissioning a data center http://docs.datastax.com/en/cassandra/2.0/cassandra/operations/ops_decomission_dc_t.html tells me to run a full repair and then decommission each node. Isn't decommissioning going to hand over all data anyway? Then why is the repair necessary? In step 3 of those instructions you reduce the number of replicas in the departing DC to 0. The departing DC no longer owns ranges at this point, and no longer is responsible for replicas. It therefore does no streaming (except maybe hints?) when you decommission nodes. =Rob
Re: Decommission datacenter - repair?
Yes, but will not handover the data to any node, it rather intimates that other nodes of the replicas so that they rebalance the nodes with the help of repair. Best Regards, Kiran.M.K. On Jun 5, 2015 6:38 PM, Jens Rantil jens.ran...@tink.se wrote: Hi Kiran, So, am I understanding you correctly that a decommissioning node only will hand over its data to a single node? If it would hand it over to all other replica nodes, I see that essentially as an implicit repair. Am I wrong? Thanks, Jens On Fri, Jun 5, 2015 at 2:27 PM, Kiran mk coolkiran2...@gmail.com wrote: Hi Jens, If you decommission a data center, The data residing in the Data Center which you are planning for decommission has to be balanced to the nodes of the other data center satisfying RF. Hence Repair is required. Best Regards, Kiran.M.K. On Fri, Jun 5, 2015 at 5:45 PM, Jens Rantil jens.ran...@tink.se wrote: Hi, I asked this on IRC earlier today, but didn't get any response; Datastax's documentation on Decommissioning a data center http://docs.datastax.com/en/cassandra/2.0/cassandra/operations/ops_decomission_dc_t.html tells me to run a full repair and then decommission each node. Isn't decommissioning going to hand over all data anyway? Then why is the repair necessary? Cheers, Jens -- Jens Rantil Backend engineer Tink AB Email: jens.ran...@tink.se Phone: +46 708 84 18 32 Web: www.tink.se Facebook https://www.facebook.com/#!/tink.se Linkedin http://www.linkedin.com/company/2735919?trk=vsrp_companies_res_phototrkInfo=VSRPsearchId%3A1057023381369207406670%2CVSRPtargetId%3A2735919%2CVSRPcmpt%3Aprimary Twitter https://twitter.com/tink -- Best Regards, Kiran.M.K. -- Jens Rantil Backend engineer Tink AB Email: jens.ran...@tink.se Phone: +46 708 84 18 32 Web: www.tink.se Facebook https://www.facebook.com/#!/tink.se Linkedin http://www.linkedin.com/company/2735919?trk=vsrp_companies_res_phototrkInfo=VSRPsearchId%3A1057023381369207406670%2CVSRPtargetId%3A2735919%2CVSRPcmpt%3Aprimary Twitter https://twitter.com/tink
