From owner-freebsd-doc@freebsd.org Tue Dec 1 07:51:31 2015 Return-Path: Delivered-To: freebsd-doc@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 1E71AA3D48A for ; Tue, 1 Dec 2015 07:51:31 +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 mx1.freebsd.org (Postfix) with ESMTPS id 0A74011B9 for ; Tue, 1 Dec 2015 07:51:31 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from bugs.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id tB17pUQQ020540 for ; Tue, 1 Dec 2015 07:51:30 GMT (envelope-from bugzilla-noreply@freebsd.org) From: bugzilla-noreply@freebsd.org To: freebsd-doc@FreeBSD.org Subject: [Bug 204929] fs_optim and fs_minfree default value is 10% in man fs(5),while newfs(8),tunefs(8) is 8% Date: Tue, 01 Dec 2015 07:51:31 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Documentation X-Bugzilla-Component: Documentation X-Bugzilla-Version: Latest X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Some People X-Bugzilla-Who: amutu@amutu.com X-Bugzilla-Status: New X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: freebsd-doc@FreeBSD.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter Message-ID: 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-doc@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Documentation project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 01 Dec 2015 07:51:31 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D204929 Bug ID: 204929 Summary: fs_optim and fs_minfree default value is 10% in man fs(5),while newfs(8),tunefs(8) is 8% Product: Documentation Version: Latest Hardware: amd64 OS: Any Status: New Severity: Affects Some People Priority: --- Component: Documentation Assignee: freebsd-doc@FreeBSD.org Reporter: amutu@amutu.com this from fs(5): The fs_minfree element gives the minimum acceptable percentage of file system blocks that may be free. If the freelist drops below this level only the super-user may continue to allocate blocks. The fs_minfree e= le=E2=80=90 ment may be set to 0 if no reserve of free blocks is deemed necessary, however severe performance degradations will be observed if the file s= ys=E2=80=90 tem is run at greater than 90% full; thus the default value of fs_minf= ree is 10%. The element fs_optim specifies whether the file system should try to min=E2= =80=90 imize the time spent allocating blocks, or if it should attempt to min= i=E2=80=90 mize the space fragmentation on the disk. If the value of fs_minfree (see above) is less than 10%, then the file system defaults to optimiz= ing for space to avoid running out of full sized blocks. If the value of minfree is greater than or equal to 10%, fragmentation is unlikely to = be problematical, and the file system defaults to optimizing for time. this from newfs(8): -m free-space The percentage of space reserved from normal users; the minimum free space threshold. The default value used is defined by MINFREE from , currently 8%. See tunefs(8) for more details on how to set this option. -o optimization (space or time). The file system can either be instructed to = try to minimize the time spent allocating blocks, or to try to min= i=E2=80=90 mize the space fragmentation on the disk. If the value of min= =E2=80=90 free (see above) is less than 8%, the default is to optimize f= or space; if the value of minfree is greater than or equal to 8%, the default is to optimize for time. See tunefs(8) for more details on how to set this option. this from tunefs: -m minfree Specify the percentage of space held back from normal users; t= he minimum free space threshold. The default value used is 8%. Note that lowering the threshold can adversely affect perfor= =E2=80=90 mance: =C2=B7 Settings of 5% and less force space optimization to a= lways be used which will greatly increase the overhead for file writes. =C2=B7 The file system's ability to avoid fragmentation will= be reduced when the total free space, including the reserve, drops below 15%. As free space approaches zero, throughput can degrade by up to a factor of three over the performance obtained at a 10% threshold. If the value is raised above the current usage level, users wi= ll be unable to allocate files until enough files have been delet= ed to get under the higher threshold. --=20 You are receiving this mail because: You are the assignee for the bug.=