From owner-freebsd-stable@FreeBSD.ORG Mon Feb 15 16:54:49 2010 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 5211110656A9 for ; Mon, 15 Feb 2010 16:54:49 +0000 (UTC) (envelope-from artemb@gmail.com) Received: from mail-iw0-f175.google.com (mail-iw0-f175.google.com [209.85.223.175]) by mx1.freebsd.org (Postfix) with ESMTP id 142158FC08 for ; Mon, 15 Feb 2010 16:54:48 +0000 (UTC) Received: by iwn5 with SMTP id 5so1929657iwn.9 for ; Mon, 15 Feb 2010 08:54:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:sender:received:in-reply-to :references:date:x-google-sender-auth:message-id:subject:from:to:cc :content-type:content-transfer-encoding; bh=P67gEQvaCwFLa+xIiOAPs1oeRs08Jio8HQd294OhM/w=; b=ai49KclE+bMsErS0sQwue415Ur0FBA2qE+w58hjLBqRUN8mQVJvRIUiebgK88tvGNv jhX3EbXjAdfKXFSlK0SalQozj+rYIyV008eEW8PER88wNQFItc6TfQt6LgyvjSflty5s 8oUwhcG4Cc8XUL7lMQDlx7fvaMBDVBWJUKy3Y= DomainKey-Signature: a=rsa-sha1; c=nofws; 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; b=wAQwOeHeR+C2cK3m8r1WilcaNSdHuBIWQsqH55+6h8+VXDYbujcK6YGTtAI/LAaqlr iGXy35chCSQ4ePmiAFauj/Fb3JtkhYtTX+SLRpznjpxBokYuPQSt0XIdu+36Ux7bgb13 BMUgudGDRa7geouLW1LifOMig/0QHDmsj5kUc= MIME-Version: 1.0 Sender: artemb@gmail.com Received: by 10.231.147.199 with SMTP id m7mr5643404ibv.87.1266252888230; Mon, 15 Feb 2010 08:54:48 -0800 (PST) In-Reply-To: <20100215161105.14071eiflhc9le68@webmail.leidinger.net> References: <20100215090756.GA54764@icarus.home.lan> <20100215105000.101326yj01j0f64g@webmail.leidinger.net> <20100215122744.GA57382@icarus.home.lan> <20100215161105.14071eiflhc9le68@webmail.leidinger.net> Date: Mon, 15 Feb 2010 08:54:48 -0800 X-Google-Sender-Auth: 96546ad3d5fbdc38 Message-ID: From: Artem Belevich To: Alexander Leidinger Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: freebsd-stable@freebsd.org, Jeremy Chadwick Subject: Re: hardware for home use large storage X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 15 Feb 2010 16:54:49 -0000 >> * vm.kmem_size >> * vm.kmem_size_max > > I tried kmem_size_max on -current (this year), and I got a panic during u= se, > I changed kmem_size to the same value I have for _max and it didn't panic > anymore. It looks (from mails on the lists) that _max is supposed to give= a > max value for auto-enhancement, but at least it was not working with ZFS > last month (and I doubt it works now). It used to be that vm.kmem_size_max needed to be bumped to allow for larger vm.kmem_size. It's no longer needed on amd64. Not sure about i386. vm.kmem_size still needs tuning, though. While vm.kmem_size_max is no longer a limit, there are other checks in place that result in default vm.kmem_size being a bit on the conservative side for ZFS. >> Then, when it comes to debugging problems as a result of tuning >> improperly (or entire lack of), the following counters (not tunables) >> are thrown into the mix as "things people should look at": >> >> =A0kstat.zfs.misc.arcstats.c >> =A0kstat.zfs.misc.arcstats.c_min >> =A0kstat.zfs.misc.arcstats.c_max > > c_max is vfs.zfs.arc_max, c_min is vfs.zfs.arc_min. > >> =A0kstat.zfs.misc.arcstats.evict_skip >> =A0kstat.zfs.misc.arcstats.memory_throttle_count >> =A0kstat.zfs.misc.arcstats.size > > I'm not very sure about size and c... both represent some kind of current > size, but they are not the same. arcstats.c -- adaptive ARC target size. I.e. that's what ZFS thinks it can grow ARC to. It's dynamically adjusted based on when/how ZFS is back-pressured for memory. arcstats.size -- current ARC size arcstats.p -- portion of arcstats.c that's used by "Most Recently Used" items. What's left of arcstats.c is used by "Most Frequently Used" items. --Artem