Rebalancing (newbie alert)

Marcin Krol mrkafk at gmail.com
Tue May 18 14:48:10 EDT 2010


Hello everyone,

I'm a total newbie with Riak and Erlang, reading the docs for now to see 
whether it could be evaluated positively for our purposes.

I have a few questions, mostly related to rebalancing across vnodes in 
case of failure of one node or physical addition of new servers.

1. I vaguely recall one of Riak authors replying to someone here that it 
is not possible to know where particular bucket resides, i.e. at which 
vnode.

If so, how can one say after one physical node crashed & burned (say, 
its hard drive failed totally) or another physical node was added that 
key/bucket pairs have indeed rebalanced across entire logical "ring"?

Is it possible to watch such process of rebalancing via some interface?

2. is it possible to obtain information how many "copies" particular 
bucket has in the ring? I don't mean configuration information, but in 
fact the situation when one physical node has crashed.

3. Backups. Is it safe to just dump a live filesystem (e.g. using 
dump/restore) of a physical riak node and that means that I have a 
reliable backup? Or is like files of an opened relational database - 
might work but this is not the way it should be done?

Is there some backup & restore utility for a physical riak node that 
allows to quickly dump its buckets into, say, one huge backup file?


-- 

Regards,
mk

--
Premature optimization is the root of all fun.




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