From owner-freebsd-fs@FreeBSD.ORG Thu Aug 29 15:59:29 2013 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id DC45188E for ; Thu, 29 Aug 2013 15:59:28 +0000 (UTC) (envelope-from fjwcash@gmail.com) Received: from mail-qe0-x22b.google.com (mail-qe0-x22b.google.com [IPv6:2607:f8b0:400d:c02::22b]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 9E6922365 for ; Thu, 29 Aug 2013 15:59:28 +0000 (UTC) Received: by mail-qe0-f43.google.com with SMTP id t7so312514qeb.30 for ; Thu, 29 Aug 2013 08:59:27 -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=cqNWVb0Uo3bU9p10twVQS3BgWcOWTPOitYue5Z8L3ho=; b=GgTgvR4VzahUPZvWlSlqW4ZFMUJbAIJCY9th+lugX9pv+GG7v80OaSo2zsZqL8hnbV JY1rIMJz9dI2bCpdzXvtCOa1DEj66SSQnM/sU5gh7TFx6xmHmnHjF9RxgSN2L42AUIcr GvBaswgoJF+kWdkoC2BWBa4EJPSUAGS4AsPlN6DsDA1oSV29NBcY8XnkU5vYus399/U+ d5uoyclw7aPC8CWpjDl/D16gmyE4cdnmOrptDe5fE36mfhjEZ7hu0a/Zch8tKAuBXSlt 7PcN3szTBoqSvyTH6DR/a1x3dX0sdWoUaKtj0QtvDFoOi3uRa5Fti9t2xd/WBhI42n3o aSqw== MIME-Version: 1.0 X-Received: by 10.49.58.132 with SMTP id r4mr4997488qeq.10.1377791967867; Thu, 29 Aug 2013 08:59:27 -0700 (PDT) Received: by 10.49.1.98 with HTTP; Thu, 29 Aug 2013 08:59:27 -0700 (PDT) In-Reply-To: References: <1079189088.15197172.1377784177805.JavaMail.root@uoguelph.ca> Date: Thu, 29 Aug 2013 08:59:27 -0700 Message-ID: Subject: Re: NFS on ZFS pure SSD pool From: Freddie Cash To: "Sam Fourman Jr." Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.14 Cc: FreeBSD FS 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: Thu, 29 Aug 2013 15:59:29 -0000 On Thu, Aug 29, 2013 at 7:16 AM, Sam Fourman Jr. wrote: > On Thu, Aug 29, 2013 at 9:49 AM, Rick Macklem > wrote: > > Also, I think there are tunables for the metadata cache in ZFS, which > > might be useful for increasing the metadata cache sizes, since the probes > > will be checking metadata (attributes). > > Can does anyone here on the list, have clues on where to start with ZFS > metadata turntables, and a command or two to profile the kernel for CPU > usage? > This will show you how many bytes of the ARC are being used by metadata: sysctl vfs.zfs.arc_meta_used You can tune what the max is via: sysctl vfs.zfs.arc_meta_limit The default setting is 12.5% (one eighth) of the ARC. On our servers running dedupe, we set this to around 80% of the ARC, and set the secondarycache ZFS property to "metadata", in order to keep the DDT in ARC/L2ARC. You may want to play with the arc_meta_limit a bit. -- Freddie Cash fjwcash@gmail.com