From owner-freebsd-questions@FreeBSD.ORG Sun Feb 8 09:48:38 2009 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 085051065674 for ; Sun, 8 Feb 2009 09:48:38 +0000 (UTC) (envelope-from kris@FreeBSD.org) Received: from kennaway-macbookpro.local (freefall.freebsd.org [IPv6:2001:4f8:fff6::28]) by mx1.freebsd.org (Postfix) with ESMTP id 42C858FC0A; Sun, 8 Feb 2009 09:48:37 +0000 (UTC) (envelope-from kris@FreeBSD.org) Message-ID: <498D87BD.3040305@FreeBSD.org> Date: Sat, 07 Feb 2009 14:08:13 +0100 From: Kris Kennaway User-Agent: Thunderbird 2.0.0.19 (Macintosh/20081209) MIME-Version: 1.0 To: Tim Judd References: <1E37AE87F15C4E34B6EB1002AADEB87A@desktop2002> <498A7F31.30206@gmail.com> In-Reply-To: <498A7F31.30206@gmail.com> Content-Type: text/plain; charset=ISO-8859-9; format=flowed Content-Transfer-Encoding: 7bit Cc: Yavuz , freebsd-questions@freebsd.org Subject: Re: is there any way to increase disk performance ? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 08 Feb 2009 09:48:38 -0000 Tim Judd wrote: > Yavuz wrote: >> I have freebsd7 (amd64 bit) and sata2 disk 7200 rpm. >> >> it's running mail server which has services like pop3,imap,smtp and >> webmail on this machine. >> >> When I type systat 1 -vmstat on command line, even I rarely see that >> disk usage hits 100%. >> I have no problem as ram and cpu. they is enough. >> >> is there any way to increase disk performance without causing any >> problem ? >> > > So in one second, the disk hits 100% utilization, weather it's reading > or writing data to disk. You said above that "I rarely see" -- so even > though, as a server, you're running slow spindles, you are doing pretty > good. > > I've no real experience with a site that's (for example) been > slashdotted, to test what is tolerable, and what's not. But as I > currently guess, an OVERALL average between 25% to 33% is about as much > as I would ever tax a server for CONSISTENT averages. > > So if you're seeing it rarely, such as when somebody hits webmail and > takes 1 second of constant disk read to serve the content, I'd be happy > there... > > I don't think you have a problem, when you put your concern into the > broader scope of 1 minute, 1 hour, 1 day or 1 week. It'll be very > difficult to never see 100% in 1 second no matter how powerful the > machine is. Make sure you understand that gstat's "%busy" column does not tell you how close to capacity your disk is, it tells you what % of time it is handling I/O. Since modern drives can have many commands queued at any given time, those are not the same thing. To understand whether your disk is overloaded, look at the ms/r and ms/w times. Kris