Return-Path: X-Original-To: apmail-cassandra-commits-archive@www.apache.org Delivered-To: apmail-cassandra-commits-archive@www.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 52E8A1176F for ; Sun, 17 Aug 2014 00:23:21 +0000 (UTC) Received: (qmail 48142 invoked by uid 500); 17 Aug 2014 00:23:21 -0000 Delivered-To: apmail-cassandra-commits-archive@cassandra.apache.org Received: (qmail 48105 invoked by uid 500); 17 Aug 2014 00:23:21 -0000 Mailing-List: contact commits-help@cassandra.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: dev@cassandra.apache.org Delivered-To: mailing list commits@cassandra.apache.org Received: (qmail 48091 invoked by uid 99); 17 Aug 2014 00:23:21 -0000 Received: from arcas.apache.org (HELO arcas.apache.org) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Sun, 17 Aug 2014 00:23:21 +0000 Date: Sun, 17 Aug 2014 00:23:21 +0000 (UTC) From: "Jonathan Ellis (JIRA)" To: commits@cassandra.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Assigned] (CASSANDRA-7386) JBOD threshold to prevent unbalanced disk utilization 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/CASSANDRA-7386?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Jonathan Ellis reassigned CASSANDRA-7386: ----------------------------------------- Assignee: Ryan McGuire (was: Robert Stupp) > JBOD threshold to prevent unbalanced disk utilization > ----------------------------------------------------- > > Key: CASSANDRA-7386 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7386 > Project: Cassandra > Issue Type: Improvement > Components: Core > Reporter: Chris Lohfink > Assignee: Ryan McGuire > Priority: Minor > Fix For: 2.1.1 > > Attachments: 7386-v1.patch, 7386v2.diff, Mappe1.ods, mean-writevalue-7disks.png, patch_2_1_branch_proto.diff, sstable-count-second-run.png > > > Currently the pick the disks are picked first by number of current tasks, then by free space. This helps with performance but can lead to large differences in utilization in some (unlikely but possible) scenarios. Ive seen 55% to 10% and heard reports of 90% to 10% on IRC. With both LCS and STCS (although my suspicion is that STCS makes it worse since harder to be balanced). > I purpose the algorithm change a little to have some maximum range of utilization where it will pick by free space over load (acknowledging it can be slower). So if a disk A is 30% full and disk B is 5% full it will never pick A over B until it balances out. -- This message was sent by Atlassian JIRA (v6.2#6252)