From owner-freebsd-bugs@freebsd.org Fri Jul 27 18:53:36 2018 Return-Path: Delivered-To: freebsd-bugs@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 D76A81053C12 for ; Fri, 27 Jul 2018 18:53:35 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mailman.ysv.freebsd.org (mailman.ysv.freebsd.org [IPv6:2001:1900:2254:206a::50:5]) by mx1.freebsd.org (Postfix) with ESMTP id 5ED4082E12 for ; Fri, 27 Jul 2018 18:53:35 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.ysv.freebsd.org (Postfix) id 234551053C11; Fri, 27 Jul 2018 18:53:35 +0000 (UTC) Delivered-To: bugs@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 0170A1053C10 for ; Fri, 27 Jul 2018 18:53:35 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.ysv.freebsd.org (mxrelay.ysv.freebsd.org [IPv6:2001:1900:2254:206a::19:3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mxrelay.ysv.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 7C6F282E11 for ; Fri, 27 Jul 2018 18:53:34 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2001:1900:2254:206a::16:76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.ysv.freebsd.org (Postfix) with ESMTPS id C2BE11F7E6 for ; Fri, 27 Jul 2018 18:53:33 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id w6RIrXWB064498 for ; Fri, 27 Jul 2018 18:53:33 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id w6RIrXho064496 for bugs@FreeBSD.org; Fri, 27 Jul 2018 18:53:33 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 229670] ZFS ARC limit vfs.zfs.arc_max from /boot/loader.conf is not respected Date: Fri, 27 Jul 2018 18:53:32 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: 11.2-RELEASE X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Many People X-Bugzilla-Who: leif@ofWilsonCreek.com X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: bugs@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.27 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 27 Jul 2018 18:53:36 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D229670 --- Comment #13 from Leif Pedersen --- So I looked back at this today, and I found that even after having returned maxvnodes to the default, I still see it overrunning arc_max persistently by almost 2x. I can lower maxvnodes below the default (179499), and then arc_m= ax is respected. Below are stats on the same system which has 6GB of RAM with arc_max set to 256MB, starting with maxvnodes at the default and then lower= ing it. Granted, one can reasonably argue that anyone capable of tinkering with arc= _max should be capable of tinkering with maxvnodes also. However, it is rather astonishing since there are suggestions to crank up maxvnodes to improve performance [wiki/ZFSTuningGuide] and to lower arc_max for small systems, b= ut no mention of one affecting the other. So I'm adding this data to be of hel= p if this is considered a significant bug. $ sysctl vfs.zfs.arc_max vfs.zfs.arc_max: 268435456 $ sysctl kern.maxvnodes kern.maxvnodes: 179499 $ top last pid: 95789; load averages: 0.14, 0.16, 0.11=20=20=20=20=20=20=20= =20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20 up 8+21:45:16 10:27:57 40 processes: 2 running, 38 sleeping CPU: 0.0% user, 0.0% nice, 0.0% system, 0.0% interrupt, 100% idle Mem: 20M Active, 251M Inact, 2769M Wired, 2856M Free ARC: 456M Total, 87M MFU, 105M MRU, 1600K Anon, 8149K Header, 255M Other 40M Compressed, 154M Uncompressed, 3.87:1 Ratio Swap:=20 Lowering kern.maxvnodes below the default: $ sysctl kern.maxvnodes=3D10240 kern.maxvnodes: 179499 -> 10240 $ top last pid: 96130; load averages: 0.06, 0.12, 0.09=20=20=20=20=20=20=20= =20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20 up 8+21:50:03 10:32:44 42 processes: 1 running, 41 sleeping CPU: 0.4% user, 0.0% nice, 0.4% system, 0.0% interrupt, 99.2% idle Mem: 21M Active, 233M Inact, 2773M Wired, 2868M Free ARC: 148M Total, 43M MFU, 29M MRU, 1600K Anon, 7678K Header, 66M Other 40M Compressed, 154M Uncompressed, 3.86:1 Ratio Swap: --=20 You are receiving this mail because: You are the assignee for the bug.=