From owner-freebsd-fs@freebsd.org Fri Aug 26 15:46:20 2016 Return-Path: Delivered-To: freebsd-fs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 7646DB70F36 for ; Fri, 26 Aug 2016 15:46:20 +0000 (UTC) (envelope-from lkateley@kateley.com) Received: from mail-it0-x230.google.com (mail-it0-x230.google.com [IPv6:2607:f8b0:4001:c0b::230]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 3C1BEB74 for ; Fri, 26 Aug 2016 15:46:20 +0000 (UTC) (envelope-from lkateley@kateley.com) Received: by mail-it0-x230.google.com with SMTP id x131so338696824ite.0 for ; Fri, 26 Aug 2016 08:46:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kateley-com.20150623.gappssmtp.com; s=20150623; h=reply-to:subject:references:to:from:organization:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding; bh=plt6XKBZqbOD4MTUY1dEj1hsEPJSvZRPWAIR2g9PPYA=; b=jL2Jg3Nq8sdV6AljTPXvU2BX/OkM1mGdizvn/Fi89DzAkOxWMhytjPQaJsF+ztWi3Q eLQc0b6HLh3w/TCuaWs+6KO8nfQtO0I96teU4XhNYjai4i7Uo9rXCEa+S0ocGhj4i77U KmVH13VsnzckEOJpryEfWqxUgqmRbZa0MYqBqx6l1kVucv9NBNbiZOjPFXt1EDOcn/bS 4zx43LrEPTN0NsgZ4nbWH5iYnNWqi9o/B4xrUiNeJN2dxnZ6AZZcmKB5bwDh6yigD/AW R4AHPiuPW4dHUTiRoYdU3sJKWJknQNXyXFFhNLo25vFA4wCTRgglwQx3B2tVL/TtMgs7 vySg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:reply-to:subject:references:to:from:organization :message-id:date:user-agent:mime-version:in-reply-to :content-transfer-encoding; bh=plt6XKBZqbOD4MTUY1dEj1hsEPJSvZRPWAIR2g9PPYA=; b=TmY5Cf80qMDnsYagRajf1kGYh6ah60dMC+5An5e+x6XBZQ7iBfOorkc6kqAFX0s7KH k818AXg5w2dbSMs2VNWq6jMkiyr7qnilgMX49jeoqubroIIlG2h8ksgid9wrtVbYk5YM dxvdhudySLy9ZVDGTRuYm3NTb07sJNlxBrTCUGr2fkmE5gWAN/3KT0TyOReuk6cTyn7G HXvO41BV0Z9nw7Dh6Cco5LBzVpfRRb7f5BWWSiP413ibuBWO0dgBRSYbYSgygwY1ww1o 6RFuAaGEtx9XMlKhalAyCe8LKp18z/Rx32HdvTznIBE5q/SO8wrRAqPWBDyoVqUlRUW8 njkQ== X-Gm-Message-State: AE9vXwMihtAmaYnoBQhv1fyk3PWTOKjylzCLLgM+7z6urpD93liNuMOYbJY4y8c58AaeXQ== X-Received: by 10.107.9.42 with SMTP id j42mr4766488ioi.33.1472226379092; Fri, 26 Aug 2016 08:46:19 -0700 (PDT) Received: from Kateleyco-iMac.local (c-50-188-36-30.hsd1.mn.comcast.net. [50.188.36.30]) by smtp.googlemail.com with ESMTPSA id i80sm7881791ita.5.2016.08.26.08.46.18 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 26 Aug 2016 08:46:18 -0700 (PDT) Reply-To: linda@kateley.com Subject: Re: [ZFS] ARC accounting bug ? References: <5B8C6663-5D21-4C03-AC69-CB7E70D3A6C2@gmail.com> <067ac0ed-1f2d-c9fb-de4d-ed5da62fe10c@internetx.com> <9EAAEEC5-0FFF-474D-9AD0-4447CD6B549B@gmail.com> <91665D7B-D2EA-4A7F-BE8D-67BE238DAF6B@gmail.com> <9A3B2699-B077-4F72-90A5-63D7E22BE652@gmail.com> To: freebsd-fs@freebsd.org From: Linda Kateley Organization: Kateley Company Message-ID: <453b967d-4139-c6b6-a27a-223ed4d92c74@kateley.com> Date: Fri, 26 Aug 2016 10:46:17 -0500 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <9A3B2699-B077-4F72-90A5-63D7E22BE652@gmail.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 26 Aug 2016 15:46:20 -0000 Metadata updates when you access a file. Atime is most often updated and you will miss. If you are running vm's on zfs I always recommend to turn off atime updates. Metadata is usually tiny so you probably won't see disk activity On 8/26/16 10:27 AM, Ben RUBSON wrote: > I'm sorry but I still can't find out where do these ARC demand metadata misses come from. > In addition, why they are not cached, as my ARC is 1% used. > And why I don't see any disk activity to honour them. > > I would really be glad if you could enlighten me :) > > Many thanks again, > > Ben > > > >> On 26 Aug 2016, at 14:28, Ben RUBSON wrote: >> >> Yes Juergen, metadata only stores in ARC files' info (location in pool and some other useful info), not the user data. >> >> I think "find" only needs metadata, as it does not read the files' content. >> Which can be "verified" because : >> - there is no IO at all on the pool (after the first find loop, once ARC has the needed metadata) ; >> - there is no ARC demand data at all. >> But I may be wrong, so of course feel free to correct me. Thank you. >> >> Thank you for the links, I already read them before posting here, but I may have missed something. >> >> Ben >> >>> On 26 Aug 2016, at 14:16, InterNetX - Juergen Gotteswinter wrote: >>> >>> so, you know the difference between >>> >>> - metadata >>> - data >>> >>> ? >>> >>> if yes, what is your find actually doing in this case? >>> >>> regarding arc >>> >>> http://dtrace.org/blogs/brendan/2012/01/09/activity-of-the-zfs-arc/ >>> https://www.patpro.net/blog/index.php/2014/03/19/2628-zfs-primarycache-all-versus-metadata/ >>> >>> >>> >>> Am 26.08.2016 um 14:06 schrieb Ben RUBSON: >>>> Juergen, thank you for your answer. >>>> So where do you think these ARC misses come from ? I can't find out :S >>>> Thank you ! >>>> >>>>> On 26 Aug 2016, at 14:01, InterNetX - Juergen Gotteswinter wrote: >>>>> >>>>> no bug, everything like i whould expect >>>>> >>>>> Am 26.08.2016 um 11:40 schrieb Ben RUBSON: >>>>>> uname -v >>>>>> FreeBSD 11.0-RC2 #0 r304729: Wed Aug 24 06:59:03 UTC 2016 root@releng2.nyi.freebsd.org:/usr/obj/usr/src/sys/GENERIC > _______________________________________________ > freebsd-fs@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org"