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From Adam Fuchs <afu...@apache.org>
Subject Re: Advice on increasing ingest rate
Date Tue, 08 Apr 2014 21:35:51 GMT
MIke,

What version of Accumulo are you using, how many tablets do you have, and
how many threads are you using for minor and major compaction pools? Also,
how big are the keys and values that you are using?

Here are a few settings that may help you:
1. WAL replication factor (tserver.wal.replication). This defaults to 3
replicas (the HDFS default), but if you set it to 2 it will give you a
performance boost without a huge hit to reliability.
2. Ingest buffer size (tserver.memory.maps.max), also known as the
in-memory map size. Increasing this generally improves the efficiency of
minor compactions and reduces the number of major compactions that will be
required down the line. 4-8 GB is not unreasonable.
3. Make sure your WAL settings are such that the size of a log
(tserver.walog.max.size) multiplied by the number of active logs
(table.compaction.minor.logs.threshold) is greater than the in-memory map
size. You probably want to accomplish this by bumping up the number of
active logs.
4. Increase the buffer size on the BatchWriter that the clients use. This
can be done with the setBatchWriterOptions method on the
AccumuloOutputFormat.

Cheers,
Adam



On Tue, Apr 8, 2014 at 4:47 PM, Mike Hugo <mike@piragua.com> wrote:

> Hello,
>
> We have an ingest process that operates via Map Reduce, processing a large
> set of XML files and  inserting mutations based on that data into a set of
> tables.
>
> On a 5 node cluster (each node has 64G ram, 20 cores, and ~600GB SSD) I
> get 400k inserts per second with 20 mapper tasks running concurrently.
>  Increasing the number of concurrent mapper tasks to 40 doesn't have any
> effect (besides causing a little more backup in compactions).
>
> I've increased the table.compaction.major.ratio and increased the number
> of concurrent allowed compactions for both min and max compaction but each
> of those only had negligible impact on ingest rates.
>
> Any advice on other settings I can tweak to get things to move more
> quickly?  Or is 400k/second a reasonable ingest rate?  Are we at a point
> where we should consider generating r files like the bulk ingest example?
>
> Thanks in advance for any advice.
>
> Mike
>

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