From owner-freebsd-fs@FreeBSD.ORG Wed May 15 00:23:59 2013 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id 8BB8CFEF for ; Wed, 15 May 2013 00:23:59 +0000 (UTC) (envelope-from jdc@koitsu.org) Received: from qmta06.emeryville.ca.mail.comcast.net (qmta06.emeryville.ca.mail.comcast.net [IPv6:2001:558:fe2d:43:76:96:30:56]) by mx1.freebsd.org (Postfix) with ESMTP id 5A065960 for ; Wed, 15 May 2013 00:23:59 +0000 (UTC) Received: from omta20.emeryville.ca.mail.comcast.net ([76.96.30.87]) by qmta06.emeryville.ca.mail.comcast.net with comcast id byhp1l0011smiN4A60Py8v; Wed, 15 May 2013 00:23:58 +0000 Received: from koitsu.strangled.net ([67.180.84.87]) by omta20.emeryville.ca.mail.comcast.net with comcast id c0Px1l00K1t3BNj8g0PxwU; Wed, 15 May 2013 00:23:58 +0000 Received: by icarus.home.lan (Postfix, from userid 1000) id 7B63373A33; Tue, 14 May 2013 17:23:57 -0700 (PDT) Date: Tue, 14 May 2013 17:23:57 -0700 From: Jeremy Chadwick To: Daniel Kalchev Subject: Re: NFS Performance issue against NetApp Message-ID: <20130515002357.GA21753@icarus.home.lan> References: <1966772823.291493.1368362883964.JavaMail.root@erie.cs.uoguelph.ca> <5190335D.9090105@hub.org> <20130513005858.GA73875@icarus.home.lan> <94661399-66AC-4E83-B39B-0426442BB84C@hub.org> <12D600DE-CBAB-40C6-B166-083DE7018E7E@digsys.bg> MIME-Version: 1.0 Content-Type: text/plain; charset=unknown-8bit Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <12D600DE-CBAB-40C6-B166-083DE7018E7E@digsys.bg> User-Agent: Mutt/1.5.21 (2010-09-15) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net; s=q20121106; t=1368577438; bh=Pq1c3ZvKrev6bTZx37oLzldmMAP8mAGVzLcvm+g7yes=; h=Received:Received:Received:Date:From:To:Subject:Message-ID: MIME-Version:Content-Type; b=BDJOXXs1B1qeTAt1eWXE+CMqJEG3MBWiXQvz0ghTWfCu5ycoNocbZgy0jM3Qq54eS PxiRitGmvYlVtuQBGc4kJJXn8L+mu7Pu08LdL587GoMNRwkg/XOWsZIkrYPUTylsGw VWrHTVcD1p0LZQgHCC/L5GjFD6l9kcDNGrmvcu3HqHi44sG0U18SNu8XUd3ItgEUT2 sPBS10NahekRwlYR+36i5NcsnZ4Tw/eFVJgAxaB0vojDxh0xF/K1j72+e/khRUST1i fzpv132aGHLeAtNQXrgw+Zp1qBV4Uo4dY6CUgxbfuR4LL7M3UBZqlC4oIf0qRSbz+h AEj1x4sraxSLw== Cc: "freebsd-fs@freebsd.org" X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 15 May 2013 00:23:59 -0000 On Wed, May 15, 2013 at 03:19:21AM +0300, Daniel Kalchev wrote: > > > > >> Probably off-topic but worth pointing out: I do not know about Solaris, > >> but Linux has multiple layers of caching, and is well-known for doing > >> things like caching (and aggregating!) reads/writes to **block** devices > >> (this is why on Linux you have to make sure to avoid caching your > >> application use O_DIRECT with open(2) or other mechanisms -- the BSDs do > >> not do this, block devices are always non-cached). > > > > Caching *should* only come into play after the first run of the application … the first run after a reboot of the server shouldn't have anything in cache yet for caching to come into play > > > > Or, instead of issuing 30 separate NFS calls over the network, issue just one. With more latency the difference will be more pronounced. > > I believe Jeremy was referring more to the aggregating aspect, which might produce significant difference for poorly written software. Thanks Daniel -- yes, correct. :-) -- | Jeremy Chadwick jdc@koitsu.org | | UNIX Systems Administrator http://jdc.koitsu.org/ | | Mountain View, CA, US | | Making life hard for others since 1977. PGP 4BD6C0CB |