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From Stack <st...@duboce.net>
Subject Re: HBase poor write performance
Date Tue, 08 Mar 2016 17:20:19 GMT
On Tue, Mar 8, 2016 at 8:28 AM, Akmal Abbasov <akmal.abbasov@icloud.com>

> Hi,
> I'm testing HBase to choose the right hardware configurations for a heavy
> write use case. I'm testing using YCSB.
The cluster consist of 2 masters, and 5 regionservers(4 cores, 14GB ram,
> 4x512GB SSD).
> I've created a new table in HBase, presplit it to 50 regions. I'm running
> 3 clients each running 50 threads, to insert data.

What happens if you double the number of clients?

> I'm using the default HBase settings.

Our defaults are intentionally conservative set for broad appeal. For now,
there is an expectation that configs are adjusted to suit the loadings.

> After running few tests, I can see that the cluster is underutilized, in
> fact memory usage is around 30%.

Which memory? Java heap? Or the systems' memory? If java heap, we make
broad allocations for cache and write-time memstore. You might allocate
more to memstore if you are write-centric (Later versions of hbase try to
do this ergonomically).

> The main problem I see for now is compactions, compactionQueueLength is
> growing very fast, and compaction process is always running.

Compactions running all the time while you are under write load is
'normal'. How are you seeing this manifest as a 'problem'?

Show us  a bit of your log from a regionserver and take a few thread dumps
while it is running so we can make suggestion.

> I found that there are hbase.regionserver.thread.compaction.small and hbase.regionserver.thread.compaction.large
> but couldn't find information regarding their default values.

Yes. This stuff is missing from the doc, in code only. Lets figure if they
need adjustment first.

> I am also planing to increase the regions number and the memstore size to
> increase utilization of the cluster and performance.
> Which other settings should be tuned to improve both utilization and
> performance?

You've browsed this section http://hbase.apache.org/book.html#performance ?

> Thank you.

> I'm using HBase 0.98.7 and regionserver heap size is 7GB.

Can you use a later HBase? 1.2.0 just got released.

> Regards, Akmal

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