Hmm.. good to find out, thanks for the reference! This explains the time differences between repairs in different DCs.
But I think using -local and -pr should still be supported simultaneously, since you may want to repair nodes sequentially in the local DC (-local) without re-repairing ranges of neighbor nodes (-pr). On Wed, Jun 25, 2014 at 1:48 PM, Sylvain Lebresne <sylv...@datastax.com> wrote: > I see. Well, you shouldn't use both "-local" and "-pr" together, they > don't make sense together. Which is the reason why their combination will > be rejected in 2.0.9 (you can check > https://issues.apache.org/jira/browse/CASSANDRA-7317 for details). > Basically, the result of using both is that lots of stuffs don't get > repaired. > > > On Wed, Jun 25, 2014 at 6:11 PM, Paulo Ricardo Motta Gomes < > paulo.mo...@chaordicsystems.com> wrote: > >> 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 >> > > -- *Paulo Motta* Chaordic | *Platform* *www.chaordic.com.br <http://www.chaordic.com.br/>* +55 48 3232.3200
