Thanks Tom... Yes I did read that but I couldn't deduce the outcome if n is decreased. John talks about data loss, but am actually observing a different result... perhaps am missing something!
On Wed, Jul 27, 2016 at 6:11 PM, Tom Santero <tsant...@gmail.com> wrote: > Vikram, > > John Daily wrote a fantastic blog series that places your question in > context and then answers it. > > > http://basho.com/posts/technical/understanding-riaks-configurable-behaviors-part-1/ > > Tom > > On Wed, Jul 27, 2016 at 4:07 PM, Vikram Lalit <vikramla...@gmail.com> > wrote: > >> Hi - I have a Riak node with n_val=3, r=2, w=2 and have just one >> key-object stored there-in. I'm trying to test various configurations to >> better understand the system and have the following observations - some >> dont seem to align with my understanding so far, so appreciate if someone >> can throw some light please... Thanks! >> >> 1. n=3, r=2, w=2: Base state, 1 key-value pair. >> >> 2. Change to n=2, r=2, w=2: When I query from my client, I randomly see 1 >> or 2 values being fetched. In fact, the number of keys fetched is 1 or 2, >> randomly changing each time the client queries the db. Ideally, I would >> have expected that if we reduce the n_val, there would be data loss from >> one of the vnodes. And that for this scenario, I would still expect only 1 >> (remaining) key-value pair to be read from the remaining two vnodes that >> has the data. Note that I dont intend to make such a change in production >> as cognizant of the recommendation to never decrease the value of n, but >> have done so only to test out the details. >> >> 3. Then change to n=2, r=1, w=1: I get the same alternating result as >> above, i.e. 1 or 2 values being fetched. >> >> 4. Then change to n=1, r=1, w=1: I get 3 key-value pairs, all identical, >> from the database. Again, are these all siblings? >> >> _______________________________________________ >> riak-users mailing list >> riak-users@lists.basho.com >> http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com >> >> >
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