From owner-freebsd-fs@FreeBSD.ORG Thu Mar 27 20:34:13 2014 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 9577F643 for ; Thu, 27 Mar 2014 20:34:13 +0000 (UTC) Received: from mail-wg0-x22b.google.com (mail-wg0-x22b.google.com [IPv6:2a00:1450:400c:c00::22b]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 2FF6516A for ; Thu, 27 Mar 2014 20:34:13 +0000 (UTC) Received: by mail-wg0-f43.google.com with SMTP id x13so2812089wgg.2 for ; Thu, 27 Mar 2014 13:34:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=LqIlYMn/xQtxSuBYPacbrC7UiUI/fvewlVP6Z5yfeTQ=; b=ru6kBXcMNbfXpLLVVJ/2CWhxLHxY+HK3z0aYIBUxrnI9Q2TM4PC9fRBR/J5eL53fAv 19us+NSQaW+hZQgBjnzvl1RERgTS2SFRJpO5mMxSmShRZAA/AJfaQ8ZP162cfeHcNLvu Vdo7hlYQ5dMNCzR9S1rZP62xSytAQSIKY/iuNayAVLyG/xaO99V0ZcbC08XS1Ykrg+z4 V0a0VhgcjyvJxQxCUKRlwNgb4JAkigIB+t6othWkvQn6bOPnKEIL9z93u2o0T6J7CX7r SirTltDfFNQdt6XF/uRQj4JA72U5dzIQbHEmEjqsOTQq0gtWQIC0mvmQfBT60vP04J4A WftA== MIME-Version: 1.0 X-Received: by 10.180.77.200 with SMTP id u8mr7839462wiw.48.1395952451408; Thu, 27 Mar 2014 13:34:11 -0700 (PDT) Received: by 10.216.146.195 with HTTP; Thu, 27 Mar 2014 13:34:11 -0700 (PDT) In-Reply-To: <20140327114018.6d50b666@suse3.ewadmin.local> References: <20140327114018.6d50b666@suse3.ewadmin.local> Date: Thu, 27 Mar 2014 21:34:11 +0100 Message-ID: Subject: Re: zfs l2arc warmup From: Joar Jegleim To: Rainer Duffner Content-Type: text/plain; charset=UTF-8 Cc: "freebsd-fs@freebsd.org" X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 27 Mar 2014 20:34:13 -0000 > Don't you need RAM for the L2ARC, too? > > http://www.richardelling.com/Home/scripts-and-programs-1/l2arc > > > I'd just max-out the RAM on the DL370 - you'd need to do that anyway, > according to the above spread-sheet.... > yeah, it does. At the moment I've got 2x480GB ssd for l2arc and 144GB ram, though I haven't found a way to calculate if I have enough ram or not I've seen posts that make me suspect I had enough ram for this setup. The link from Johan Hendriks https://blogs.oracle.com/brendan/entry/l2arc_screenshots mention that in the bottom actually " It costs some DRAM to reference the L2ARC, at a rate proportional to record size. For example, it currently takes about 15 Gbytes of DRAM to reference 600 Gbytes of L2ARC - at an 8 Kbyte ZFS record size. If you use a 16 Kbyte record size, that cost would be halve - 7.5 Gbytes. This means you shouldn't, for example, configure a system with only 8 Gbytes of DRAM, 600 Gbytes of L2ARC, and an 8 Kbyte record size - if you did, the L2ARC would never fully populate. " My two 480GB ssd's will probably be full by tomorrow, they're currently at 686GB and got about 207GB left to fill. I wonder how I can read out how much ram is used for l2arc reference (?) would that be the 'HEADER' value from top in 9.2-RELEASE (the ARC line) it was around 3GB yesterday and now I see it's climbed to about 6.3GB . (got 128KB record size) . On 27 March 2014 11:40, Rainer Duffner wrote: > Am Thu, 27 Mar 2014 08:50:06 +0100 > schrieb Joar Jegleim : > >> Hi list ! >> >> I struggling to get a clear understanding of how the l2arc get warm >> ( zfs). It's a FreeBSD 9.2-RELEASE server. >> > >> The thing is with this particular pool is that it serves somewhere >> between 20 -> 30 million jpegs for a website. The front page of the >> site will for every reload present a mosaic of about 36 jpegs, and the >> jpegs are completely randomly fetched from the pool. >> I don't know what jpegs will be fetched at any given time, so I'm >> installing about 2TB of l2arc ( the pool is about 1.6TB today) and I >> want the whole pool to be available from the l2arc . >> >> >> Any input on my 'rsync solution' to warmup the l2arc is much >> appreciated :) >> >> > > > > Don't you need RAM for the L2ARC, too? > > http://www.richardelling.com/Home/scripts-and-programs-1/l2arc > > > I'd just max-out the RAM on the DL370 - you'd need to do that anyway, > according to the above spread-sheet.... > > > > > -- ---------------------- Joar Jegleim Homepage: http://cosmicb.no Linkedin: http://no.linkedin.com/in/joarjegleim fb: http://www.facebook.com/joar.jegleim AKA: CosmicB @Freenode ----------------------