>From my own experiments performance difference is huge even on 
sequential R/W operations (up to 300%) when you do local File I/O vs HDFS File 
I/O

Overhead of HDFS I/O is substantial to say the least.

Best regards,
Vladimir Rodionov
Principal Platform Engineer
Carrier IQ, www.carrieriq.com
e-mail: [email protected]

________________________________________
From: Todd Lipcon [[email protected]]
Sent: Saturday, December 04, 2010 12:30 PM
To: [email protected]
Subject: Re: Local sockets

Hi Leen,

Check out HDFS-347 for more info on this. I hope to pick this back up in
2011 - in 2010 we mostly focused on stability above performance in HBase's
interactions with HDFS.

Thanks
-Todd

On Sat, Dec 4, 2010 at 12:28 PM, Leen Toelen <[email protected]> wrote:

> Hi,
>
> has anyone tested the performance impact (when there is a hdfs
> datanode and a hbase node on the same machine) of using unix domain
> sockets communication or shared memory ipc using nio? I guess this
> should make a difference on reads?
>
> Regards,
> Leen
>



--
Todd Lipcon
Software Engineer, Cloudera

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