From owner-freebsd-fs@FreeBSD.ORG Mon Sep 19 21:37:48 2011 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 14126106566B for ; Mon, 19 Sep 2011 21:37:48 +0000 (UTC) (envelope-from artemb@gmail.com) Received: from mail-yw0-f54.google.com (mail-yw0-f54.google.com [209.85.213.54]) by mx1.freebsd.org (Postfix) with ESMTP id C4D1F8FC12 for ; Mon, 19 Sep 2011 21:37:47 +0000 (UTC) Received: by ywp17 with SMTP id 17so5535363ywp.13 for ; Mon, 19 Sep 2011 14:37:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; bh=uiKAo0uahMiO51/yoeDCmK5lvPmtUX+XkW94AqbTHZg=; b=qWZpTpeH7UgA6dteP1rLKLmAAKPtzMTpRltwUszdqAM60F5GI+Lq4h1LlLS5P9KJtI dg0qWHUHYH1tpvFFv7UYjTQ2iXaIF3lTWdy0nKh7zLwHyQC3uh/x4zmggcCsvdDEF9Mu lpogQD9kYBHQJahxru38ot9Kib6vbzImSLs4M= MIME-Version: 1.0 Received: by 10.236.191.71 with SMTP id f47mr17151872yhn.125.1316468267019; Mon, 19 Sep 2011 14:37:47 -0700 (PDT) Sender: artemb@gmail.com Received: by 10.236.102.147 with HTTP; Mon, 19 Sep 2011 14:37:46 -0700 (PDT) In-Reply-To: References: <1316459220.35419.YahooMailClassic@web121209.mail.ne1.yahoo.com> Date: Mon, 19 Sep 2011 14:37:46 -0700 X-Google-Sender-Auth: jYfNjYhXadTc0Q1YCbTiXOFfyBs Message-ID: From: Artem Belevich To: Freddie Cash Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: Jason Usher , freebsd-fs@freebsd.org Subject: Re: ZFS obn FreeBSD hardware model for 48 or 96 sata3 paths... X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 19 Sep 2011 21:37:48 -0000 On Mon, Sep 19, 2011 at 1:27 PM, Freddie Cash wrote: >> Can I explicitly cache metadata/dirs in RAM, and cache file data in L2AR= C ? > > > No. =A0Data that does not go into the ARC can never go into the L2ARC. = =A0IOW, > if you set primarycache=3Dmetadata and secondarycache=3Ddata, you will ne= ver see > anything in L2ARC. > > At least, that's the understanding I've come to based on posts on the > zfs-discuss mailing list. =A0And it does jive with what I was seeing on o= ur > storage servers. Indeed. I didn't think of that. L2ARC is populated by the data that gets evicted from ARC. So, if ARC is metadata only, whatever spills into L2ARC would be metadata only, too... > It's too bad, because it would be a nice setup, ordered from fastert to > slowest: =A0ARC for metadata, L2ARC for file data, pool for permanent sto= rage. That would indeed be nice. --Artem