Return-Path: X-Original-To: apmail-hadoop-hdfs-user-archive@minotaur.apache.org Delivered-To: apmail-hadoop-hdfs-user-archive@minotaur.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id ABFC7E378 for ; Fri, 1 Feb 2013 17:53:25 +0000 (UTC) Received: (qmail 49905 invoked by uid 500); 1 Feb 2013 17:53:21 -0000 Delivered-To: apmail-hadoop-hdfs-user-archive@hadoop.apache.org Received: (qmail 49630 invoked by uid 500); 1 Feb 2013 17:53:20 -0000 Mailing-List: contact user-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: user@hadoop.apache.org Delivered-To: mailing list user@hadoop.apache.org Received: (qmail 49623 invoked by uid 99); 1 Feb 2013 17:53:20 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 01 Feb 2013 17:53:20 +0000 X-ASF-Spam-Status: No, hits=3.2 required=5.0 tests=FREEMAIL_REPLY,HTML_MESSAGE,RCVD_IN_DNSWL_NONE,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: domain of vijayjtuk@hotmail.com designates 157.55.1.174 as permitted sender) Received: from [157.55.1.174] (HELO dub0-omc2-s35.dub0.hotmail.com) (157.55.1.174) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 01 Feb 2013 17:53:14 +0000 Received: from DUB118-DS1 ([157.55.1.136]) by dub0-omc2-s35.dub0.hotmail.com with Microsoft SMTPSVC(6.0.3790.4675); Fri, 1 Feb 2013 09:52:53 -0800 X-EIP: [TA+Bc15tTknbjnrlUNvvkkplxZ4QKt4v7584ANXijZY=] X-Originating-Email: [vijayjtuk@hotmail.com] Message-ID: From: Vijay Thakorlal To: References: In-Reply-To: Subject: RE: Reg Too many fetch-failures Error Date: Fri, 1 Feb 2013 17:52:52 +0000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0094_01CE00A4.F5B1CD70" X-Mailer: Microsoft Office Outlook 12.0 Thread-Index: Ac4AjykWA5/AU0SkThOdUnzxbRq5KgAEyzjA Content-Language: en-gb X-OriginalArrivalTime: 01 Feb 2013 17:52:53.0071 (UTC) FILETIME=[F5515DF0:01CE00A4] X-Virus-Checked: Checked by ClamAV on apache.org ------=_NextPart_000_0094_01CE00A4.F5B1CD70 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Hi Manoj, As you may be aware this means the reduces are unable to fetch intermediate data from TaskTrackers that ran map tasks - you can try: * increasing tasktracker.http.threads so there are more threads to handle fetch requests from reduces. * decreasing mapreduce.reduce.parallel.copies : so fewer copy / fetches are performed in parallel It could also be due to a temporary DNS issue. See slide 26 of this presentation for potential causes for this message: http://www.slideshare.net/cloudera/hadoop-troubleshooting-101-kate-ting-clou dera Not sure why you did not receive the problem before but was it the same data or different data? Did you have other jobs running on your cluster? Hope that helps Regards Vijay From: Manoj Babu [mailto:manoj444@gmail.com] Sent: 01 February 2013 15:09 To: user@hadoop.apache.org Subject: Reg Too many fetch-failures Error Hi All, I am getting Too many fetch-failures exception. What might be the reason for this exception, For same size of data i dint face this error earlier and there is change in code. How to avoid this? Thanks in advance. Cheers! Manoj. ------=_NextPart_000_0094_01CE00A4.F5B1CD70 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Hi Manoj,

 

As you may be aware this means the reduces are unable to fetch = intermediate data from TaskTrackers that ran map tasks – you can = try:

* increasing tasktracker.http.threads so there are more threads to = handle fetch requests from reduces.

* decreasing mapreduce.reduce.parallel.copies : so fewer copy / = fetches are performed in parallel

 

It could also be due to a temporary DNS = issue.

 

See slide 26 of this presentation for potential causes for this = message: http://www.slideshare.net/cloudera/hadoop-troubleshootin= g-101-kate-ting-cloudera

 

Not sure why you did not receive the problem before but was it the = same data or different data? Did you have other jobs running on your = cluster?

 

Hope that helps

 

Regards

Vijay

 

From:= = Manoj Babu [mailto:manoj444@gmail.com]
Sent: 01 February 2013 = 15:09
To: user@hadoop.apache.org
Subject: Reg Too = many fetch-failures Error

 

Hi = All,

 

I = am getting Too = many fetch-failures exception.

What might be the = reason for this exception, For same size of data i dint face this error = earlier and there is change in code.

How to avoid = this?

 

Thanks in = advance.

 

Cheers!

Manoj.

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