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From Nate McCall <n...@thelastpickle.com>
Subject Re: Too many SSTables after rebalancing cluster (LCS)
Date Wed, 27 Aug 2014 22:02:33 GMT
Try turning down 'tombstone_threshold' to something like '0.05' from it's
default of '0.2.' This will cause the SSTable to be considered for
tombstone only compactions more frequently (if %5 of the columns are
tombstones instead of 20%).

For a bit more info, see:
http://www.datastax.com/documentation/cql/3.0/cql/cql_reference/compactSubprop.html


On Tue, Aug 26, 2014 at 1:38 PM, Paulo Ricardo Motta Gomes <
paulo.motta@chaordicsystems.com> wrote:

> Hey folks,
>
> After adding more nodes and moving tokens of "old" nodes to rebalance the
> ring, I noticed that the "old" nodes had significant more data then the
> newly bootstrapped nodes, even after cleanup.
>
> I noticed that the old nodes had a much larger number of SSTables on LCS
> CFs, and most of them located on the last level:
>
> Node N-1 (old node): [1, 10, 102/100, 173, 2403, 0, 0, 0, 0] (total:2695)
>
> *Node N (new node): [1, 10, 108/100, 214, 0, 0, 0, 0, 0] (total: 339)*Node
> N+1 (old node): [1, 10, 87, 113, 1076, 0, 0, 0, 0] (total: 1287)
>
> Since these sstables have a lot of tombstones, and they're not updated
> frequently, they remain in the last level forever, and are never cleaned.
>
> What is the solution here? The good old "change to STCS and then back to
> LCS", or is there something less brute force?
>
> Environment: Cassandra 1.2.16 - non-vnondes
>
> Any help would be very much appreciated.
>
> Cheers,
>
> --
> *Paulo Motta*
>
> Chaordic | *Platform*
> *www.chaordic.com.br <http://www.chaordic.com.br/>*
> +55 48 3232.3200
>



-- 
-----------------
Nate McCall
Austin, TX
@zznate

Co-Founder & Sr. Technical Consultant
Apache Cassandra Consulting
http://www.thelastpickle.com

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