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From Ara Ebrahimi <>
Subject AccumuloFileOutputFormat tuning
Date Sat, 03 Jan 2015 05:46:00 GMT

I’m trying to optimize our map/reduce job which generates RFiles using AccumuloFileOutputFormat.
We have a specific time window and within that time window we need to generate a predefined
amount of simulation data and in terms of number of core we also have an upper bound we can
use. Disks are also fixed at 4 per node and they are all SSDs. So I can’t employ more machines
or more disks or cores to achieve higher write/s numbers.

So far we’ve managed to utilize 100% of all available cores and the SSD disks are also highly
utilized. I’m trying to reduce processing time and we are willing to waste more disk space
to achieve higher data generation speed. The data itself is 10s of columns of floating numbers,
all serialized to fixed 9-byte values which doesn’t lend well to compression. With no compression
and replication set to 1 we can generate the same amount of data in almost half the time.
With snappy it’s almost 10% more data generation time compared to no compression and almost
twice more size on disk for the all the generated RFiles.

dataBlockSize doesn’t seem to change anything for non-compressed data. indexBlockSize also
didn't change anything (tried 64K vs the default 128K).

Any other tricks I could employ to achieve higher write/s numbers?



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