From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wido den Hollander Subject: Re: Journal size of each disk Date: Mon, 11 Jun 2012 10:35:21 +0200 Message-ID: <4FD5ADC9.3080208@widodh.nl> References: <8512670932FB654F81AF0FEF1BE6D49D017E52FD@WHQBEMAIL1.whq.wistron> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from smtp01.mail.pcextreme.nl ([109.72.87.137]:44848 "EHLO smtp01.mail.pcextreme.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750795Ab2FKIfY (ORCPT ); Mon, 11 Jun 2012 04:35:24 -0400 In-Reply-To: <8512670932FB654F81AF0FEF1BE6D49D017E52FD@WHQBEMAIL1.whq.wistron> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Eric_YH_Chen@wiwynn.com Cc: ceph-devel@vger.kernel.org, Chris_YT_Huang@wiwynn.com, Victor_CY_Chang@wiwynn.com Hi, On 06/11/2012 08:47 AM, Eric_YH_Chen@wiwynn.com wrote: > Dear all: > > I would like to know if the journal size influence the performance > of disk. > > If the size of each of my disk is 1T, how much size should I prepare > for the journal? > You journal should be able to hold the writes for a short period of time, something like 10 ~ 20 seconds. If your machine is on a 1Gbit line it will do something like 100MB/sec of writes. 100MB * 20 seconds = 2000MB So a journal of something like 2GB should be enough. You can always scale it bigger to 4GB, that won't hurt anything. So it doesn't depend on the size of your data disk, but depends on how fast the writes are coming in. Wido > Thanks for any comment. > > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html