Return-Path: X-Original-To: apmail-cassandra-user-archive@www.apache.org Delivered-To: apmail-cassandra-user-archive@www.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 160596640 for ; Thu, 7 Jul 2011 01:38:03 +0000 (UTC) Received: (qmail 78120 invoked by uid 500); 7 Jul 2011 01:38:00 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 77953 invoked by uid 500); 7 Jul 2011 01:38:00 -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 77945 invoked by uid 99); 7 Jul 2011 01:37:59 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 07 Jul 2011 01:37:59 +0000 X-ASF-Spam-Status: No, hits=2.2 required=5.0 tests=HTML_MESSAGE,MIME_QP_LONG_LINE,RCVD_IN_DNSWL_NONE,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: local policy) Received: from [208.113.200.5] (HELO homiemail-a53.g.dreamhost.com) (208.113.200.5) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 07 Jul 2011 01:37:52 +0000 Received: from homiemail-a53.g.dreamhost.com (localhost [127.0.0.1]) by homiemail-a53.g.dreamhost.com (Postfix) with ESMTP id 6E0AF138062 for ; Wed, 6 Jul 2011 18:37:25 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; c=nofws; d=thelastpickle.com; h=subject :references:from:content-type:in-reply-to:message-id:date:to :content-transfer-encoding:mime-version; q=dns; s= thelastpickle.com; b=2YMuNy1r1WiQB8t27Mn4cOBoJGtDWIdotAIHkebli+x /vcgTbXy6SpAgy25GaNsWhU6kDHRHskjXGGaSLaNGIlXRu1Erx69vDzhwZfg5ldo 4FnvzgHQ4dywhmUnsbs2VXsLebgOa0uqkSli/Y2rKxNDQLyVV11foqgF6CbT3S4g = DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=thelastpickle.com; h= subject:references:from:content-type:in-reply-to:message-id:date :to:content-transfer-encoding:mime-version; s=thelastpickle.com; bh=pMkbu9veRHMIAOEbn6p2WENdF6M=; b=QnfDbO7KAPEi5zY9WQEkgIi35GgU Ag1gNZI82iu2qLvtGcwvyClOgGyvF8zQ71MF+QZtevgeIGhOFVfZde+ZsuGHBXV1 /36qNKW5bUtZAlJPIKIPGOKlek0ZXzOrmHzBXw7L5f7AaksuMy14zwXH8MMCs5eW F2hm0CFDNaOSwhM= Received: from [115.189.55.21] (unknown [115.189.55.21]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) (Authenticated sender: aaron@thelastpickle.com) by homiemail-a53.g.dreamhost.com (Postfix) with ESMTPSA id 773D6138059 for ; Wed, 6 Jul 2011 18:37:24 -0700 (PDT) Subject: Re: memory References: <7DA4B654C7FEB24C9998EE4867BEE93EBC7C13@CNMAIL12.cn.utstarcom.com> From: Aaron Morton Content-Type: multipart/alternative; boundary=Apple-Mail-4-982969586 X-Mailer: iPad Mail (8J3) In-Reply-To: <7DA4B654C7FEB24C9998EE4867BEE93EBC7C13@CNMAIL12.cn.utstarcom.com> Message-Id: Date: Thu, 7 Jul 2011 13:37:16 +1200 To: "user@cassandra.apache.org" Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (iPad Mail 8J3) X-Virus-Checked: Checked by ClamAV on apache.org --Apple-Mail-4-982969586 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii That advice is a little out of date, specially in the future world of 0.8 me= mory management, see http://thelastpickle.com/2011/05/04/How-are-Memtables-m= easured/ Cheers ----------------- Aaron Morton Freelance Cassandra Developer @aaronmorton http://www.thelastpickle.com On 6/07/2011, at 5:51 PM, Donna Li wrote: > All: > For a rough rule of thumb, Cassandra's internal datastructures will requir= e about memtable_throughput_in_mb * 3 * number of hot CFs + 1G + internal ca= ches. > =20 > Why cassandra need so much memory? What is the 1G memory used for? > =20 > =20 > Best Regards > Donna li --Apple-Mail-4-982969586 Content-Transfer-Encoding: 7bit Content-Type: text/html; charset=utf-8
That advice is a little out of date, specially in the future world of 0.8 memory management, see http://thelastpickle.com/2011/05/04/How-are-Memtables-measured/

Cheers
-----------------
Aaron Morton
Freelance Cassandra Developer
@aaronmorton

On 6/07/2011, at 5:51 PM, Donna Li <donna.li@utstar.com> wrote:

All:

For a rough rule of thumb, Cassandra's internal datastructures will require about memtable_throughput_in_mb * 3 * number of hot CFs + 1G + internal caches.

 

Why cassandra need so much memory? What is the 1G memory used for?

 

 

Best Regards

Donna li

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