Return-Path: X-Original-To: apmail-hadoop-hdfs-issues-archive@minotaur.apache.org Delivered-To: apmail-hadoop-hdfs-issues-archive@minotaur.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 997A2CE70 for ; Mon, 5 Jan 2015 16:43:35 +0000 (UTC) Received: (qmail 515 invoked by uid 500); 5 Jan 2015 16:43:36 -0000 Delivered-To: apmail-hadoop-hdfs-issues-archive@hadoop.apache.org Received: (qmail 450 invoked by uid 500); 5 Jan 2015 16:43:36 -0000 Mailing-List: contact hdfs-issues-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: hdfs-issues@hadoop.apache.org Delivered-To: mailing list hdfs-issues@hadoop.apache.org Received: (qmail 438 invoked by uid 99); 5 Jan 2015 16:43:36 -0000 Received: from arcas.apache.org (HELO arcas.apache.org) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 05 Jan 2015 16:43:36 +0000 Date: Mon, 5 Jan 2015 16:43:36 +0000 (UTC) From: "Daryn Sharp (JIRA)" To: hdfs-issues@hadoop.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Commented] (HDFS-7270) Add congestion signaling capability to DataNode write protocol MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-JIRA-FingerPrint: 30527f35849b9dde25b450d4833f0394 [ https://issues.apache.org/jira/browse/HDFS-7270?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14264755#comment-14264755 ] Daryn Sharp commented on HDFS-7270: ----------------------------------- Conceptually this appears to be a useful feature. Could you please elaborate on how you intend to implement its use in a followup jira? I'd like to evaluate if your approach will improve or exasperate current issues in our environment. How will a DN signal congestion? When will it signal congestion? Ie. In a premature ack since prior ack easily becomes stale? What will the client do? On a minor note, please avoid the ImmutableList and its Builder usage instead of a primitive array since it adds little value compared to more boxing and GC overhead. > Add congestion signaling capability to DataNode write protocol > -------------------------------------------------------------- > > Key: HDFS-7270 > URL: https://issues.apache.org/jira/browse/HDFS-7270 > Project: Hadoop HDFS > Issue Type: Improvement > Components: datanode > Reporter: Haohui Mai > Assignee: Haohui Mai > Attachments: HDFS-7270.000.patch, HDFS-7270.001.patch, HDFS-7270.002.patch > > > When a client writes to HDFS faster than the disk bandwidth of the DNs, it saturates the disk bandwidth and put the DNs unresponsive. The client only backs off by aborting / recovering the pipeline, which leads to failed writes and unnecessary pipeline recovery. > This jira proposes to add explicit congestion control mechanisms in the writing pipeline. -- This message was sent by Atlassian JIRA (v6.3.4#6332)