Mailing-List: contact user-help@hbase.apache.org; run by ezmlm
Precedence: bulk
Reply-To: user@hbase.apache.org
Received-SPF: pass (athena.apache.org: domain of saint.ack@gmail.com
 designates 209.85.214.169 as permitted sender)
MIME-Version: 1.0
Sender: saint.ack@gmail.com
In-Reply-To: <50756F61.8000606@di.uminho.pt>
References: <50756F61.8000606@di.uminho.pt>
Date: Wed, 10 Oct 2012 20:24:59 -0700
Message-ID: 
 <CADcMMgExonu7MNgKVhyMtKZ2vL05KC3ZdLMzV7gBtbhe2feSOQ@mail.gmail.com>
Subject: Re: HBase Tuning
From: Stack <stack@duboce.net>
To: user@hbase.apache.org
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

On Wed, Oct 10, 2012 at 5:51 AM, Ricardo Vila=E7a <rmvilaca@di.uminho.pt> w=
rote:
> However, when adding an additional client node, with also 400 clients,
> the latency increases 3 times,
> but the RegionServers remains idle more than 80%. I had tried different
> values for the hbase.regionserver.handler.count and also
> for the hbase.client.ipc.pool size and type but without any improvement.
>

I was going to suggest that it sounded like all handlers are
occupied... but it sounds like you tried upping them.

Is this going from one client node (serving 400 clients) to two client
nodes (serving 800 clients)?

Where are you measuring from?  Application side?  Can you figure if we
are binding up in HBase or in the client node?

What does a client node look like?  It is something hosting an hbase
client?  A webserver or something?

> Is there any configuration parameter that can improve the latency with
> several concurrent threads and more than one HBase client node
> and/or which JMX parameters should I monitor on RegionServers to check
> what may be causing this and how could I achieve better utilization of CP=
U
> at RegionServers?
>

It sounds like all your data is memory resident given its size and the
lack of iowait.  Is that so?  Studying the regionserver metrics, are
they fairly constant across the addition of the new client node?

St.Ack