From owner-freebsd-fs@freebsd.org Thu Jun 14 07:01:47 2018 Return-Path: Delivered-To: freebsd-fs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 70D8F1008965 for ; Thu, 14 Jun 2018 07:01:47 +0000 (UTC) (envelope-from peter@rulingia.com) Received: from vtr.rulingia.com (vtr.rulingia.com [IPv6:2001:19f0:5801:ebe:5400:1ff:fe53:30fd]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "vtr.rulingia.com", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 9488378A42 for ; Thu, 14 Jun 2018 07:01:46 +0000 (UTC) (envelope-from peter@rulingia.com) Received: from server.rulingia.com (ppp59-167-167-3.static.internode.on.net [59.167.167.3]) by vtr.rulingia.com (8.15.2/8.15.2) with ESMTPS id w5E71Yar017067 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 14 Jun 2018 17:01:40 +1000 (AEST) (envelope-from peter@rulingia.com) X-Bogosity: Ham, spamicity=0.000000 Received: from server.rulingia.com (localhost.rulingia.com [127.0.0.1]) by server.rulingia.com (8.15.2/8.15.2) with ESMTPS id w5E71Thd053419 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 14 Jun 2018 17:01:29 +1000 (AEST) (envelope-from peter@server.rulingia.com) Received: (from peter@localhost) by server.rulingia.com (8.15.2/8.15.2/Submit) id w5E71Tff053418; Thu, 14 Jun 2018 17:01:29 +1000 (AEST) (envelope-from peter) Date: Thu, 14 Jun 2018 17:01:29 +1000 From: Peter Jeremy To: Albert Shih Cc: freebsd-fs@freebsd.org Subject: Re: What append when arc full Message-ID: <20180614070129.GE88895@server.rulingia.com> References: <20180613200700.GA3156@io.chezmoi.fr> <248ad0be-2002-89b5-0c1a-3ac73d493149@ShaneWare.Biz> <20180614054333.GA7053@io.chezmoi.fr> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="1UWUbFP1cBYEclgG" Content-Disposition: inline In-Reply-To: <20180614054333.GA7053@io.chezmoi.fr> X-PGP-Key: http://www.rulingia.com/keys/peter.pgp User-Agent: Mutt/1.9.5 (2018-04-13) X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 14 Jun 2018 07:01:47 -0000 --1UWUbFP1cBYEclgG Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2018-Jun-14 07:43:33 +0200, Albert Shih wrote: >But my concern are what append if I shrink a little more the arc_max, let's >say 64G knowing I got < 30To of data. Does I'm going to loose lot of >performance ? This really depends on your workload and the disk access pattern. I suggest you install sysutils/zfs-stats and look at the various ARC hit/miss rates once your system has stabilised. You might find that tuning vfs.zfs.arc_meta_limit can also help - by default, it's 1/4 of ARC but in my experience, metadata misses are more expensive so increasing that can help. --=20 Peter Jeremy --1UWUbFP1cBYEclgG Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQKTBAEBCgB9FiEE7rKYbDBnHnTmXCJ+FqWXoOSiCzQFAlsiEsRfFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldEVF QjI5ODZDMzA2NzFFNzRFNjVDMjI3RTE2QTU5N0EwRTRBMjBCMzQACgkQFqWXoOSi CzRJ7Q//Uwc3NmYksOaFmDr9Pr7qjXY6LtmqFacIHsrQ1X7M3x873l1g10O0l1jR TTgO7ZQi+8h9KvKLpCQSZLp8ez6Nd1QX/Bx+t1Yq2lFMfOJLvk8VyfKcTtUteLjn wVHRtgBDxSezcAbyGPTVrjqHp89K9LDQu3dhw5SDU1KmFIZxOt9t4fOUMfE/o1cK qL/+D1skBY7DFABwMqL+w7HINYQDTPp3HWduBI5tsJ5NtuJrL1BRA3A6G1wT8zl4 kZCmtbyr5avEfBqaTbAqU7hs7hC9XbHgtsM0x0a0kB28I8JasA+9vC37Qu68myWD O7kSxN7UfjRQUcqmKJjeseGSVzerYsOWyF8+Tf/59Y4Rc/ULBTwzjPHl2X+aL3ca OyBb0eexwSBox9KbroBdZQHd1FvLbhqIsmIiSlINjZAuIlkidVvYuTCYq2H6d4z1 72qRn0vj89wSI2YHJkDKXwrkDNkId4rsJSFWhLhuIyrUt6Y0PIwyLOszio6hxHHA h6cBoWNeNTFlBDIiC6nHK+y4e2xN6c4pcCiXaEV2yQfA7sar6cPtmjVikTH8IuNU PEjhNAmdpLHmaw1pwzOPtFechoIGkHxaFpbgS7DUcji6RwavB22mzoBCh9qOxgt0 +uWXTU9vYBOpsH1PSvfTwMTdb64KKjyMGG83Yx+PXFaux3OCIKY= =lubT -----END PGP SIGNATURE----- --1UWUbFP1cBYEclgG--