Return-Path: Delivered-To: apmail-incubator-cassandra-user-archive@minotaur.apache.org Received: (qmail 94023 invoked from network); 26 Nov 2009 00:07:14 -0000 Received: from hermes.apache.org (HELO mail.apache.org) (140.211.11.3) by minotaur.apache.org with SMTP; 26 Nov 2009 00:07:14 -0000 Received: (qmail 17111 invoked by uid 500); 26 Nov 2009 00:07:14 -0000 Delivered-To: apmail-incubator-cassandra-user-archive@incubator.apache.org Received: (qmail 17085 invoked by uid 500); 26 Nov 2009 00:07:14 -0000 Mailing-List: contact cassandra-user-help@incubator.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: cassandra-user@incubator.apache.org Delivered-To: mailing list cassandra-user@incubator.apache.org Received: (qmail 17073 invoked by uid 99); 26 Nov 2009 00:07:14 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 26 Nov 2009 00:07:14 +0000 X-ASF-Spam-Status: No, hits=-0.0 required=10.0 tests=SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: domain of rrabah@playdom.com designates 74.125.149.77 as permitted sender) Received: from [74.125.149.77] (HELO na3sys009aog106.obsmtp.com) (74.125.149.77) by apache.org (qpsmtpd/0.29) with SMTP; Thu, 26 Nov 2009 00:07:04 +0000 Received: from source ([209.85.222.188]) by na3sys009aob106.postini.com ([74.125.148.12]) with SMTP ID DSNKSw3Gk3xsM0Tdbiv69+u6TTBZYS2BWHd2@postini.com; Wed, 25 Nov 2009 16:06:44 PST Received: by pzk26 with SMTP id 26so152683pzk.4 for ; Wed, 25 Nov 2009 16:06:43 -0800 (PST) MIME-Version: 1.0 Received: by 10.140.194.5 with SMTP id r5mr529561rvf.125.1259194003055; Wed, 25 Nov 2009 16:06:43 -0800 (PST) Date: Wed, 25 Nov 2009 16:06:43 -0800 Message-ID: Subject: Measuring load in Cassandra From: Ramzi Rabah To: cassandra-user@incubator.apache.org Content-Type: text/plain; charset=ISO-8859-1 X-Virus-Checked: Checked by ClamAV on apache.org Hi all We are trying to measure the load on cassandra nodes in production. Looking at the jconsole interface, we see a few attributes like: ReadCount, WriteCount, ReadLatency, WriteLatency. >From what I have observed of these numbers, ReadCount might be 15 one second but 14 the next one, so I can't really understand what it is trying to measure. Is it cummulative reads on this node, or reads per second? Also are these numbers accurate or are they broken? Thanks Ray