From hdfs-issues-return-229316-archive-asf-public=cust-asf.ponee.io@hadoop.apache.org Mon Aug 13 11:35:04 2018 Return-Path: X-Original-To: archive-asf-public@cust-asf.ponee.io Delivered-To: archive-asf-public@cust-asf.ponee.io Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by mx-eu-01.ponee.io (Postfix) with SMTP id 8A347180629 for ; Mon, 13 Aug 2018 11:35:03 +0200 (CEST) Received: (qmail 86716 invoked by uid 500); 13 Aug 2018 09:35:02 -0000 Mailing-List: contact hdfs-issues-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Delivered-To: mailing list hdfs-issues@hadoop.apache.org Received: (qmail 86705 invoked by uid 99); 13 Aug 2018 09:35:02 -0000 Received: from pnap-us-west-generic-nat.apache.org (HELO spamd3-us-west.apache.org) (209.188.14.142) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 13 Aug 2018 09:35:02 +0000 Received: from localhost (localhost [127.0.0.1]) by spamd3-us-west.apache.org (ASF Mail Server at spamd3-us-west.apache.org) with ESMTP id 380E11801AF for ; Mon, 13 Aug 2018 09:35:02 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at spamd3-us-west.apache.org X-Spam-Flag: NO X-Spam-Score: -110.301 X-Spam-Level: X-Spam-Status: No, score=-110.301 tagged_above=-999 required=6.31 tests=[ENV_AND_HDR_SPF_MATCH=-0.5, RCVD_IN_DNSWL_MED=-2.3, SPF_PASS=-0.001, USER_IN_DEF_SPF_WL=-7.5, USER_IN_WHITELIST=-100] autolearn=disabled Received: from mx1-lw-us.apache.org ([10.40.0.8]) by localhost (spamd3-us-west.apache.org [10.40.0.10]) (amavisd-new, port 10024) with ESMTP id ApVrZSLmF4e5 for ; Mon, 13 Aug 2018 09:35:01 +0000 (UTC) Received: from mailrelay1-us-west.apache.org (mailrelay1-us-west.apache.org [209.188.14.139]) by mx1-lw-us.apache.org (ASF Mail Server at mx1-lw-us.apache.org) with ESMTP id 2D53E5F30E for ; Mon, 13 Aug 2018 09:35:01 +0000 (UTC) Received: from jira-lw-us.apache.org (unknown [207.244.88.139]) by mailrelay1-us-west.apache.org (ASF Mail Server at mailrelay1-us-west.apache.org) with ESMTP id A2216E0E3E for ; Mon, 13 Aug 2018 09:35:00 +0000 (UTC) Received: from jira-lw-us.apache.org (localhost [127.0.0.1]) by jira-lw-us.apache.org (ASF Mail Server at jira-lw-us.apache.org) with ESMTP id 6137E23F9E for ; Mon, 13 Aug 2018 09:35:00 +0000 (UTC) Date: Mon, 13 Aug 2018 09:35:00 +0000 (UTC) From: "Kitti Nanasi (JIRA)" To: hdfs-issues@hadoop.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Updated] (HDFS-13788) Update EC documentation about rack fault tolerance 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-13788?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Kitti Nanasi updated HDFS-13788: -------------------------------- Status: Patch Available (was: Open) > Update EC documentation about rack fault tolerance > -------------------------------------------------- > > Key: HDFS-13788 > URL: https://issues.apache.org/jira/browse/HDFS-13788 > Project: Hadoop HDFS > Issue Type: Task > Components: documentation, erasure-coding > Affects Versions: 3.0.0 > Reporter: Xiao Chen > Assignee: Kitti Nanasi > Priority: Major > Attachments: HDFS-13788.001.patch > > > From http://hadoop.apache.org/docs/r3.0.0/hadoop-project-dist/hadoop-hdfs/HDFSErasureCoding.html: > {quote} > For rack fault-tolerance, it is also important to have at least as many racks as the configured EC stripe width. For EC policy RS (6,3), this means minimally 9 racks, and ideally 10 or 11 to handle planned and unplanned outages. For clusters with fewer racks than the stripe width, HDFS cannot maintain rack fault-tolerance, but will still attempt to spread a striped file across multiple nodes to preserve node-level fault-tolerance. > {quote} > Theoretical minimum is 3 racks, and ideally 9 or more, so the document should be updated. > (I didn't check timestamps, but this is probably due to {{BlockPlacementPolicyRackFaultTolerant}} isn't completely done when HDFS-9088 introduced this doc. Later there's also examples in {{TestErasureCodingMultipleRacks}} to test this explicitly.) -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-issues-unsubscribe@hadoop.apache.org For additional commands, e-mail: hdfs-issues-help@hadoop.apache.org