[infinispan-dev] ISPN-263 and handling partitions

Manik Surtani msurtani at redhat.com
Fri Apr 5 09:53:01 EDT 2013


Guys,

So this is what I have in mind for this, looking for opinions.

1.  We write a SplitBrainListener which is registered when the channel connects.  The aim of this listener is to identify when we have a partition.  This can be identified when a view change is detected, and the new view is significantly smaller than the old view.  Easier to detect for large clusters, but smaller clusters will be harder - trying to decide between a node leaving vs a partition.  (Any better ideas here?)

2.  The SBL flips a switch in an interceptor (SplitBrainHandlerInterceptor?) which switches the node to be read-only (reject invocations that change the state of the local node) if it is in the smaller partition (newView.size < oldView.size / 2).  Only works reliably for odd-numbered cluster sizes, and the issues with small clusters seen in (1) will affect here as well.

3.  The SBL can flip the switch in the interceptor back to normal operation once a MergeView is detected.

It's no way near perfect but at least it means that we can recommend enabling this and setting up an odd number of nodes, with a cluster size of at least N if you want to reduce inconsistency in your grid during partitions.

Is this even useful?

Bela, is there a more reliable mechanism to detect a split in (1)?

Cheers
Manik

--
Manik Surtani
manik at jboss.org
twitter.com/maniksurtani

Platform Architect, JBoss Data Grid
http://red.ht/data-grid




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