Thanks for the explanation, but I got slightly confused: >From my understanding, you just described the behavior of the -pr/--partitioner-range option: "Repair only the first range returned by the partitioner for the node." , so I would understand that repairs in the same CFs in different DCs with only the -pr option could take different times.
However according to the description of the -local/--in-local-dc option, it "only repairs against nodes in the same data center", but you said that "the range will be repaired for all replica in all data-centers", even with the "-local" option, or did you confuse it with "-pr" option? In any case, I'm using both "-local" and "-pr" options, what is the expected behavior in that case? Cheers, On Wed, Jun 25, 2014 at 12:46 PM, Sylvain Lebresne <sylv...@datastax.com> wrote: > TL;DR, this is not unexpected and this is perfectly fine. > > For every node, 'repair --local' will repair the "primary" (where primary > means "the first range on the ring picked by the consistent hashing for > this node given its token", nothing more) range of the node in the ring. > And that range will be repaired for all replica in all data-centers. When > you assign tokens to multiple DC, it's actually pretty common to offset the > tokens of one DC slightly compared to the other one. This will result in > the "primary" ranges being always small in one DC but not the other. But > please note that this perfectly ok, it does not imply any imbalance in > data-centers. It also don't really mean that the node of one DC actually do > a lot more work than the other ones: all nodes most likely contribute > roughly the same amount of work to the repair. It only mean that the nodes > of one DC "coordinate" more repair work that those of the other DC. Which > is not really a big deal since coordinating a repair is cheap. > > -- > Sylvain > > > On Wed, Jun 25, 2014 at 4:43 PM, Paulo Ricardo Motta Gomes < > paulo.mo...@chaordicsystems.com> wrote: > >> Hello, >> >> I'm running repair on a large CF with the "--local" flag in 2 different >> DCs. In one of the DCs the operation takes about 1 hour per node, while in >> the other it takes 10 hours per node. >> >> I would expect the times to differ, but not so much. The writes on that >> CF all come from the DC where it takes 10 hours per node, could this be the >> cause why it takes so long on this DC? >> >> Additional info: C* 1.2.16, both DCs have the same replication factor. >> >> Cheers, >> >> -- >> *Paulo Motta* >> >> Chaordic | *Platform* >> *www.chaordic.com.br <http://www.chaordic.com.br/>* >> +55 48 3232.3200 >> > > -- *Paulo Motta* Chaordic | *Platform* *www.chaordic.com.br <http://www.chaordic.com.br/>* +55 48 3232.3200
