From user-return-40001-apmail-cassandra-user-archive=cassandra.apache.org@cassandra.apache.org Mon Apr 7 11:45:14 2014 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 7CECD10646 for ; Mon, 7 Apr 2014 11:45:14 +0000 (UTC) Received: (qmail 33844 invoked by uid 500); 7 Apr 2014 11:45:11 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 33824 invoked by uid 500); 7 Apr 2014 11:45:10 -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 33816 invoked by uid 99); 7 Apr 2014 11:45:07 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 07 Apr 2014 11:45:07 +0000 X-ASF-Spam-Status: No, hits=2.5 required=5.0 tests=HTML_FONT_FACE_BAD,HTML_MESSAGE,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: local policy) Received: from [88.198.227.105] (HELO team.enercast.de) (88.198.227.105) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 07 Apr 2014 11:45:02 +0000 Received: from [172.17.2.199] (alpha.enercast.de [217.86.247.221]) (using TLSv1 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by team.enercast.de (Postfix) with ESMTPSA id B1BA22F20642 for ; Mon, 7 Apr 2014 11:44:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=enercast.de; s=mail; t=1396871079; bh=be6QATzfqzlCV0kGnq6fIV6o5/5YN5JaH6ndQoS3fcs=; h=Date:From:To:Subject:References:In-Reply-To:From; b=UwUjqbWw83t+xk6Wfx2/6ClwoMhIM/5ZrXkDaZMZQqSg6nsOEKt/lk5ChxltYWLsf D7pp7J2QUuxsldS2rcmaRGkWfvP6lt0NjNPAQHwedOgTmSlOfhYsa6TKEMKLgiQ5TL GmO/6EhoO1i2M7BalAqlb9pGBnHH2PCfWTsXCIbo= Message-ID: <53428FA5.6090606@enercast.de> Date: Mon, 07 Apr 2014 13:44:37 +0200 From: Jan Kesten User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: user@cassandra.apache.org Subject: Re: Cassandra Disk storage capacity References: <534287B1.50008@enercast.de>, In-Reply-To: Content-Type: multipart/alternative; boundary="------------000307030007000503030702" X-Virus-Checked: Checked by ClamAV on apache.org This is a multi-part message in MIME format. --------------000307030007000503030702 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Am 07.04.2014 13:24, schrieb Hari Rajendhran: > 1) I am confused why cassandra uses the entire disk space ( / > Directory) even when we specify /var/lib/cassandra/data as the > directory in Cassandra.yaml file > 2) Is it only during compaction ,cassandra will use the entire Disk > space ? > 3) What is the best way to monitor the cassandra Disk usage ?? is > there a opensource monitoring tool for this ?? Hi, if your / and /var/lib/cassandra/data are on different disks (or partitions) only /var/lib/cassandra/data will get filled entirely. Often this is not the case per default and you will have to create this mountpoints by yourself. Also keep in mind to keep commitlogs on a seperate disk from data to improve performance. The extra space is only needed during compaction - but cassandra will fire up compactions by itself, so you must keep this free space maintained all the time. This is valid for SizeTieredCompation, Leveled- or HybridCompations are "cheaper" on disk space. For the last point - there are many tools to monitor your servers inside your cluster. Nagios, Hyperic HQ and OpenNMS are some of them - you can define alerts which keep you up to date. Cheers, jan --------------000307030007000503030702 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit
Am 07.04.2014 13:24, schrieb Hari Rajendhran:
1) I am confused why cassandra uses the entire disk space ( / Directory) even when we specify /var/lib/cassandra/data as the directory in Cassandra.yaml file
2) Is it only during compaction ,cassandra will use the entire Disk space ?
3) What is the best way to monitor the cassandra Disk usage ?? is there a opensource monitoring tool for this ??

Hi,

if your / and /var/lib/cassandra/data are on different disks (or partitions) only /var/lib/cassandra/data will get filled entirely. Often this is not the case per default and you will have to create this mountpoints by yourself. Also keep in mind to keep commitlogs on a seperate disk from data to improve performance.

The extra space is only needed during compaction - but cassandra will fire up compactions by itself, so you must keep this free space maintained all the time. This is valid for SizeTieredCompation, Leveled- or HybridCompations are "cheaper" on disk space.

For the last point - there are many tools to monitor your servers inside your cluster. Nagios, Hyperic HQ and OpenNMS are some of them - you can define alerts which keep you up to date.

Cheers,
jan
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