Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932850AbcDYPfd (ORCPT ); Mon, 25 Apr 2016 11:35:33 -0400 Received: from mail-bl2on0063.outbound.protection.outlook.com ([65.55.169.63]:47514 "EHLO na01-bl2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932723AbcDYPfb (ORCPT ); Mon, 25 Apr 2016 11:35:31 -0400 Authentication-Results: spf=pass (sender IP is 63.163.107.21) smtp.mailfrom=sandisk.com; vger.kernel.org; dkim=none (message not signed) header.d=none;vger.kernel.org; dmarc=bestguesspass action=none header.from=sandisk.com; X-AuditID: ac160c69-5f3ff70000000be7-98-571e38d2783a Subject: Re: [Drbd-dev] [PATCH 05/30] drbd: Introduce new disk config option rs-discard-granularity To: Philipp Reisner , Jens Axboe , "linux-kernel@vger.kernel.org" References: <1461586077-11581-1-git-send-email-philipp.reisner@linbit.com> <1461586077-11581-6-git-send-email-philipp.reisner@linbit.com> CC: "drbd-dev@lists.linbit.com" From: Bart Van Assche Message-ID: <571E393E.1010003@sandisk.com> Date: Mon, 25 Apr 2016 08:35:26 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.2 MIME-Version: 1.0 In-Reply-To: <1461586077-11581-6-git-send-email-philipp.reisner@linbit.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrALMWRmVeSWpSXmKPExsWyRoxnke5lC7lwg6WrWS3+7znGZvHw6goW i8u75rBZvJz5mMmBxWNi8zt2j6dXjjB5tDxoY/P4vEkugCWKyyYlNSezLLVI3y6BK2Pq4l9M BTtYKn7OXMXSwHiYuYuRk0NCwESivW8lSxcjF4eQwFwmiedzetlAEkICOxglpk5Xgynae/wQ E0TRUkaJXU9aWEESwgKpEtvunmUDSYgI9DBKzHg9nRGiqptRou9mIztIFbOAtcSOxpVgNpuA kcS39zNZQGxeAS2Jj98PgU1iEVCVaP5/hhHEFhWIkFi97hozRI2gxMmZT8DqOQW8JU5egOhl FrCQmDn/PCOELS+x/e0cZpDFEgLrWCVa1l5hgvhBXeLkkvlMExiFZyGZNQtJ/ywk/QsYmVcx iuVm5hTnpqcWGJrqFSfmpWQWZ+sl5+duYoTEQ+YOxrtPvA8xCnAwKvHwfmCRDRdiTSwrrsw9 xCjBwawkwisFjCYh3pTEyqrUovz4otKc1OJDjNIcLErivG73voQJCaQnlqRmp6YWpBbBZJk4 OKUaGFXuPZ1yi7FmZWZ0e26n280rtp/DXsxX316ifX1mqhtDzrr0jYLJQRUvZFbEPU5yWKRT s9WR4fDVaa8ZE4NfGlQ5eAQeWsKne0HH+NvejNeS8RUdAd9zN+WmsJva2AdoFlhcf+2rd/af qXXyzPbi3f56Ox/en+Y0cYWZRcOtuhzPyT/SItitlFiKMxINtZiLihMBCNEjwoMCAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrCJMWRmVeSWpSXmKPExsXCtZEjRdfOUi7c4OUHcYv/e46xWTy8uoLF 4vKuOWwWL2c+ZnJg8ZjY/I7d4+mVI0weLQ/a2Dw+b5ILYInisklJzcksSy3St0vgypi6+BdT wQ6Wip8zV7E0MB5m7mLk5JAQMJHYe/wQE4gtJLCYUeLSp2gQW1ggVWLb3bNsXYxcHCICPYwS i24tZwdxhAS6GSX6bjYCORwczALWEh8WlIA0sAkYSXx7P5MFxOYV0JL4+P0QK4jNIqAq0fz/ DCOILSoQIbF63TVmiBpBiZMzn4DVcwp4S5y8ANHLLGAmMW/zQ2YIW15i+9s5zBMY+WYhaZmF pGwWkrIFjMyrGMVyM3OKc9MzCwwN9YoT81Iyi7P1kvNzNzGCw5Ezcgfj04nmhxiZODilGhhT /hi8nNXKuSlbUlZ7u8TMEtkJjRttV36d92TClZn14Rs/ltQ8U+uYde13w8W3FbJ+LE+lZvIv bOGXfbTb8NJ7uT+rNjuorc48PHEp5/46zy9vGK+3tDL8Krf4Y2lRWs04y+P5wZWrPwj8XRuW dLOMfWfLXPGcw6XZCw1sHbr0P1i9nZc6IyVYiaU4I9FQi7moOBEA7dwIHPcBAAA= X-EOPAttributedMessage: 0 X-Forefront-Antispam-Report: CIP:63.163.107.21;IPV:NLI;CTRY:US;EFV:NLI;SFV:NSPM;SFS:(10009020)(6009001)(2980300002)(438002)(24454002)(199003)(377454003)(189002)(47776003)(6806005)(64126003)(65956001)(80316001)(65806001)(77096005)(87936001)(5003600100002)(106466001)(5001770100001)(2270400002)(11100500001)(189998001)(92566002)(76176999)(5008740100001)(50986999)(54356999)(87266999)(86362001)(23676002)(65816999)(2501003)(230783001)(33656002)(2906002)(53416004)(36756003)(2950100001)(1096002)(81166005)(1220700001)(230700001)(4326007)(83506001)(586003);DIR:OUT;SFP:1101;SCL:1;SRVR:SN1PR0201MB1871;H:milsmgep15.sandisk.com;FPR:;SPF:Pass;MLV:sfv;A:1;MX:1;LANG:en; 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With setting > it to a positive value, DRBD limits and aligns its resync requests > to the rs-discard-granularity setting. If the sync source detects > all zeros in such a block, the resync target discards the range > on disk. Hello Phil, Can you explain why rs-discard-granularity is configurable instead of e.g. setting it to the least common multiple of the discard granularities of the underlying block devices at both sides? Thanks, Bart.