Return-Path: Delivered-To: apmail-cassandra-user-archive@www.apache.org Received: (qmail 19497 invoked from network); 22 Aug 2010 22:57:52 -0000 Received: from unknown (HELO mail.apache.org) (140.211.11.3) by 140.211.11.9 with SMTP; 22 Aug 2010 22:57:52 -0000 Received: (qmail 63239 invoked by uid 500); 22 Aug 2010 22:57:51 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 63197 invoked by uid 500); 22 Aug 2010 22:57:50 -0000 Mailing-List: contact user-help@cassandra.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: user@cassandra.apache.org Delivered-To: mailing list user@cassandra.apache.org Received: (qmail 63189 invoked by uid 99); 22 Aug 2010 22:57:50 -0000 Received: from Unknown (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Sun, 22 Aug 2010 22:57:50 +0000 X-ASF-Spam-Status: No, hits=0.7 required=10.0 tests=RCVD_IN_DNSWL_NONE,SPF_NEUTRAL X-Spam-Check-By: apache.org Received-SPF: neutral (nike.apache.org: local policy) Received: from [209.85.212.44] (HELO mail-vw0-f44.google.com) (209.85.212.44) by apache.org (qpsmtpd/0.29) with ESMTP; Sun, 22 Aug 2010 22:57:25 +0000 Received: by vws10 with SMTP id 10so5130806vws.31 for ; Sun, 22 Aug 2010 15:57:02 -0700 (PDT) MIME-Version: 1.0 Received: by 10.220.59.202 with SMTP id m10mr2779806vch.193.1282517822727; Sun, 22 Aug 2010 15:57:02 -0700 (PDT) Sender: scode@scode.org Received: by 10.220.203.12 with HTTP; Sun, 22 Aug 2010 15:57:02 -0700 (PDT) X-Originating-IP: [213.114.156.79] In-Reply-To: References: Date: Mon, 23 Aug 2010 00:57:02 +0200 X-Google-Sender-Auth: pnZkOPmfyRXJLNq-FXUiVMP__Tk Message-ID: Subject: Re: Cassandra Nodes Freeze/Down for ConcurrentMarkSweep GC? From: Peter Schuller To: user@cassandra.apache.org Content-Type: text/plain; charset=UTF-8 X-Virus-Checked: Checked by ClamAV on apache.org > [4] Is GC ConcurrentMarkSweep a Stop-The-World situation? Where the > JVM cannot do anything else? Hence then node is technically Down? > Correct? No; the concurrent mark/sweep phase runs concurrently with your application. CMS will cause a stop-the-world full pause it it fails to complete a CMS sweep in time and you hit the maximum heap size, but unless that happens, CMS will run concurrently (though there are stop-the-world pauses involved, that are typically very short, the mark/sweep phase is concurrent). As jbellis pointed out, you're almost certainly swapping. -- / Peter Schuller