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From Mick Semb Wever <>
Subject Re: OOM opening bloom filter
Date Mon, 12 Mar 2012 19:24:07 GMT

> > > > It's my understanding then for this use case that bloom filters are of
> > > > little importance and that i can

Ok. To summarise our actions to get us out of this situation, in hope
that it may help others one day, we did the following actions:

 1) upgrade to 1.0.7
 2) set fp_ratio=0.99
 3) set index_interval=4096
 4) restarted the node with Xmx30G
 5) run `nodetool scrub` 
      and monitor total size of bf files
      using `du -hc *-Filter.db | grep total`
 6) restart node with original Xmx setting once total bf size is under
      (scrub was running for >12hrs)
      (remaining bloom filters can be rebuilt later from normal compact)

Hopefully it will also eventuate that this cluster can run with a more
normal Xmx4G rather than the previous Xmx12G.

(2) and (3) are very much dependent on our set up using hadoop where all
reads are get_range_slice with 16k rows per request. Both could be tuned
correctly but they're the numbers that worked first up.


"When there is no enemy within, the enemies outside can't hurt you."
African proverb 

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