> At first I assume the discussion need to be moved to user-forum ( > user@ignite.apache.org).
Sorry, my mistake , duplicate to user@ignite.apache.org With best regards Alisher Alimov alimovalis...@gmail.com > On 2 Nov 2016, at 11:48, Vladislav Pyatkov <vpyat...@gridgain.com> wrote: > > Hi Alisher, > > At first I assume the discussion need to be moved to user-forum ( > user@ignite.apache.org). > > If you have 2 backups (in case you have enough nodes) this mean you can > loose 2 node, without afraid to loose data. In case you have a fail more > than the 2 nodes, it is mean you have incomplete(only part of data has > available) data. > > In general, If you are loosing more nodes than backups you are have, this > must be signal: "These inconsistent!". > > Also you can divided your nodes by specification: group of backups and > group of primary, using RendezvousAffinityFunction#setAffinityBackupFilter. > > On Wed, Nov 2, 2016 at 11:11 AM, Alisher Alimov <alimovalis...@gmail.com> > wrote: > >> Hi! >> >> I have a question about data consistency in cluster, if there are any >> mechanism for checking that cache is in consistency state (no lost >> data/partitions) >> >> For example I have a cluster with N nodes, long compute job that calculate >> monthly revenue on huge amount of data. Data is transaction log that stored >> in cache “transactions" <UUID, Float> (where key is transaction id, value >> transaction amount). Cache backups = 2. >> >> First case. >> >> 1. We load huge amount of data in cache "transactions" >> 2. All is fine >> 3. Run simple compute job that sum values in transaction log ( Float::sum >> ) >> 4. Compute job run on all nodes except n1,n2 >> 5. We lost n1 node, than n2 node that stored backup of n1 node >> 6. Ignite found that node n1 and n2 are down and rebalancing data >> 7. Compute job was completed >> >> Second case. >> >> 1. We load huge amount of data in cache "transactions" >> 2. All is fine >> 3. We lost n1 node, then n2 node that stored backup of n1 node >> 4. Ignite found that node n1 and n2 are down and rebalancing data >> 5. Run simple compute job that sum values in transaction log ( (a,b) -> >> a+b ) >> >> So questions: >> - what result we can retrieve in first case from compute job? >> - at second case we run compute job on cache that is not in consistency >> state (partitions that belongs to n1, n2 nodes was lost) but Ignite cache >> will work fine and allow us to run ComputeJob on cache and doesn’t tell us >> that some data was lost, isn’t it? >> >> >> With best regards >> Alisher Alimov >> alimovalis...@gmail.com >> >> >> >> >>
