From owner-freebsd-stable@FreeBSD.ORG Fri May 10 03:32:35 2013 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id B6D6356B for ; Fri, 10 May 2013 03:32:35 +0000 (UTC) (envelope-from fjwcash@gmail.com) Received: from mail-qc0-x22d.google.com (mail-qc0-x22d.google.com [IPv6:2607:f8b0:400d:c01::22d]) by mx1.freebsd.org (Postfix) with ESMTP id 7AED7699 for ; Fri, 10 May 2013 03:32:35 +0000 (UTC) Received: by mail-qc0-f173.google.com with SMTP id c11so2039594qcv.18 for ; Thu, 09 May 2013 20:32:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:x-received:in-reply-to:references:date:message-id :subject:from:to:cc:content-type; bh=ErG8oGaittZXOH/JrRN1xP3tzKASyIJyGDj6cZbPpIE=; b=0f6NGry1hHz9eDvgnCJR0mjl1RyP9TkLWh1NgBtVYtoOld0+ajmr5/6+Tp0dxUFEMg 46WA3cPltOMKKLeryQoio3PTaXeWR4dqLJANVKbBViheNl8zFuI1etOP2loA4RU/MUBp nA9pGanHmJCksMmP+zaAKnxKctcc3NEG4QnwUYnXve/QtlNyzaVBWam9M/QndpDrJ5Og Q7/bqdqluRiT2hBFbriNX+IDGo2UmQJZeECCyrKwrJycHlX/Tyg/ZixhH4lqg20Fi0Rk gIdL4PDeMcBjY7eucOnxuqcVyhqwtg4g/ge9VzuCauI3jf8w/zEhk1UXEr7dUIWNFoZs KJ+w== MIME-Version: 1.0 X-Received: by 10.229.60.203 with SMTP id q11mr4102616qch.78.1368156755059; Thu, 09 May 2013 20:32:35 -0700 (PDT) Received: by 10.49.1.44 with HTTP; Thu, 9 May 2013 20:32:34 -0700 (PDT) Received: by 10.49.1.44 with HTTP; Thu, 9 May 2013 20:32:34 -0700 (PDT) In-Reply-To: References: <518BA237.3030700@gmail.com> <518C450B.5070809@ShaneWare.Biz> <518C51AF.5050609@gmail.com> <20130510020628.GA98750@icarus.home.lan> Date: Thu, 9 May 2013 20:32:34 -0700 Message-ID: Subject: Re: recommended memory for zfs From: Freddie Cash To: Adam Vande More Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.14 Cc: Jeremy Chadwick , Benjamin Adams , FreeBSD Stable , Shane Ambler X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 10 May 2013 03:32:35 -0000 And the "rule of thumb" for dedupe was approx 1 GB of ARC per unique TB of data in the pool (above and beyond your normal ARC requirements). Not 1 GB of RAM per TB of disk in the pool. Very big difference between the two. :) On 2013-05-09 7:14 PM, "Adam Vande More" wrote: > On Thu, May 9, 2013 at 9:06 PM, Jeremy Chadwick wrote: > > > The advice of "1GB of RAM per 1TB of disk space" is absolute nonsense on > > numerous levels -- whoever gave this advice to Shane either has no > > understanding of how filesystems/ZFS works, or does but chose to > > simplify to the point where they're providing half-ass information. > > IIRC, that used to be the guideline for memory requirements for dedup. > > > > -- > Adam Vande More > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" >