From owner-freebsd-hackers@FreeBSD.ORG Mon Feb 9 18:33:22 2015 Return-Path: Delivered-To: freebsd-hackers@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 5D80BDE1; Mon, 9 Feb 2015 18:33:22 +0000 (UTC) Received: from na01-bl2-obe.outbound.protection.outlook.com (mail-bl2on0065.outbound.protection.outlook.com [65.55.169.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (Client CN "mail.protection.outlook.com", Issuer "MSIT Machine Auth CA 2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id C14D2AE0; Mon, 9 Feb 2015 18:33:21 +0000 (UTC) Received: from DM2PR0801MB0944.namprd08.prod.outlook.com (25.160.131.27) by DM2PR0801MB0944.namprd08.prod.outlook.com (25.160.131.27) with Microsoft SMTP Server (TLS) id 15.1.75.20; Mon, 9 Feb 2015 18:33:13 +0000 Received: from DM2PR0801MB0944.namprd08.prod.outlook.com ([25.160.131.27]) by DM2PR0801MB0944.namprd08.prod.outlook.com ([25.160.131.27]) with mapi id 15.01.0075.002; Mon, 9 Feb 2015 18:33:13 +0000 From: "Pokala, Ravi" To: John-Mark Gurney Subject: Re: Changing the MTU on a lagg device Thread-Topic: Changing the MTU on a lagg device Thread-Index: AQHQQn+0qPs6AFh2xkSO1q7r/b61upzko7MA//9+dwCAAT+aAIACmNSAgACqM4D//33OAA== Date: Mon, 9 Feb 2015 18:33:12 +0000 Message-ID: References: <20150207051012.GH58410@funkthat.com> <20150207163028.GA4965@ox> <20150209181909.GG1953@funkthat.com> In-Reply-To: <20150209181909.GG1953@funkthat.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: user-agent: Microsoft-MacOutlook/14.4.7.141117 x-originating-ip: [24.6.178.251] authentication-results: funkthat.com; dkim=none (message not signed) header.d=none; x-microsoft-antispam: BCL:0;PCL:0;RULEID:;SRVR:DM2PR0801MB0944; x-exchange-antispam-report-test: UriScan:; x-exchange-antispam-report-cfa-test: BCL:0; PCL:0; RULEID:; SRVR:DM2PR0801MB0944; x-forefront-prvs: 04825EA361 x-forefront-antispam-report: SFV:NSPM; SFS:(10009020)(6009001)(13464003)(377424004)(40100003)(87936001)(86362001)(2656002)(76176999)(19580405001)(77156002)(62966003)(122556002)(2900100001)(92566002)(19580395003)(106116001)(110136001)(46102003)(83506001)(99286002)(93886004)(66066001)(54356999)(36756003)(102836002)(50986999)(2950100001); DIR:OUT; SFP:1101; SCL:1; SRVR:DM2PR0801MB0944; H:DM2PR0801MB0944.namprd08.prod.outlook.com; FPR:; SPF:None; MLV:sfv; LANG:en; Content-Type: text/plain; charset="us-ascii" Content-ID: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: panasas.com X-MS-Exchange-CrossTenant-originalarrivaltime: 09 Feb 2015 18:33:12.3879 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: acf01c9d-c699-42af-bdbb-44bf582e60b0 X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM2PR0801MB0944 Cc: "freebsd-hackers@freebsd.org" , Navdeep Parhar X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 09 Feb 2015 18:33:22 -0000 -----Original Message----- From: John-Mark Gurney Date: 2015-02-09, Monday at 10:19 To: Ravi Pokala Cc: Navdeep Parhar , "freebsd-hackers@freebsd.org" Subject: Re: Changing the MTU on a lagg device >Hate to suggest making this more complicated, but we should leave lagg in >as consistent state as possible... Which IMO, though very surprising, is >kicking out the failed component... Leaving a mixed MTU which could drop >packets, but somewhat work seems worse... I considered as well, but I figured dropping to the lowest MTU that worked for all the components would be less disruptive than moving to the higher MTU and kicking out the failed components. I'm flexible on this; it seems to be a fairly rare corner-case, in which all options suck, so I'm happy to defer to others as to which option sucks least. :-) -Ravi