[jira] [Created] (IGNITE-2655) AffinityFunction: primary and backup copies in different locations

["Denis Magda (JIRA)" <ji...@apache.org>]

Denis Magda created IGNITE-2655:
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             Summary: AffinityFunction: primary and backup copies in different locations
                 Key: IGNITE-2655
                 URL: https://issues.apache.org/jira/browse/IGNITE-2655
             Project: Ignite
          Issue Type: Bug
            Reporter: Denis Magda
            Priority: Critical
             Fix For: 1.6


There is a use case when primary and backup copies have to be located in different racks, building, cities, etc.

A simple scenario is the following. When nodes are started they will have either "rack1" or "rack2" value in their attributes list and we will enforce that the backups won't be selected among the nodes with the same attribute.
It should be possible to filter out backups using IP addresses as well.

Presently rendezvous and fair affinity function has {{backupFilter}} that will work perfectly for the scenario above but only for cases when number of backups for a cache is equal to 1.

In case when the number of backups is bigger than one {{backupFilter}} will only guarantee that the primary is located in different location but will NOT guarantee that all the backups are spread out across different locations as well.

So we need to provide an API that will allow to spread the primary and ALL backups copies across different locations.

The proposal is to introduce {{AffinityBackupFilter}} with the following method
{{AffinityBackupFilter.isAssignable(Node n, List<Node> assigned)}}

Where n - potential backup to check, assigned - list of current partition holders, 1st is primary

{{AffinityBackupFilter}} will be set using {{affinity.setAffinityBackupFilter}}.
{{Affinity.setBackupFilter}} has to be deprecated.



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