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Add bitcask volume test results

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martinsumner 2017-02-28 21:19:46 +00:00
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docs/VOLUME.md
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@ -159,5 +159,16 @@ to be completed ..
Testing for load including 2i queries
## Riak Cluster Test - Phase 5
For larger objects, it is interesting to compare performance with between Bitcask and leveled. At the start of a pure push test it is not possible for leveled to operate at the same rate as bitcask - as bitcask is finding/updating pointer s through a NIF'd memory operation in C (whereas leveled needs to has two levels of indirect pointers which are being lazily persisted to disk).
However, as the test progresses, there should be an advantage in that leveled is not needing to read each object from disk N times on both PUT and GET - so as the scope of the database creeps beyond that covered by the page cache, and as the frequency of disk reads starts to create an I/O bottlneck then leveled throughput will become more competitive.
Here is a side-by-side on a standard Phase 1 test on i2, without sync, and with 60 threads and 16KB objects.
Riak + leveled | Riak + bitcask
:-------------------------:|:-------------------------:
![](../test/volume/cluster_five/output/summary_leveled_5n_60t_i2_16KB_nosync.png "LevelEd") | ![](../test/volume/cluster_five/output/summary_bitcask_5n_60t_i2_16KB_nosync.png "LevelDB")
Over the whole test, the bitcask-backed cluster achieves <b>16.48%</b> more throughput than leveled, but in the last hour this advantage is just <b>0.34%</b>.