From nobody Thu Jan 13 08:32:26 2022 X-Original-To: questions@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 2D1B61951CCF for ; Thu, 13 Jan 2022 08:35:00 +0000 (UTC) (envelope-from hruodr@gmail.com) Received: from mail-wr1-x42f.google.com (mail-wr1-x42f.google.com [IPv6:2a00:1450:4864:20::42f]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1D4" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4JZHmd02jhz3j3j for ; Thu, 13 Jan 2022 08:34:57 +0000 (UTC) (envelope-from hruodr@gmail.com) Received: by mail-wr1-x42f.google.com with SMTP id a5so8711023wrh.5 for ; Thu, 13 Jan 2022 00:34:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=date:from:to:subject:in-reply-to:message-id:references:mime-version; bh=cbcTBy1vA4K8807YqFE77gALyKa6C+0LW6TM1xrw0wQ=; b=ggzeol18T+RSuEwzooeiyKdpJXKF0++nxf+6b8ebz7zgleqsfB7TIqKE8JEehXCXDT P3EFZ2pOx2iXL1wnlHXMBclDzlK4MI8awIeKY35A2lHQumdhyK9os232UKcUdsiP3HB9 w6VmZJDVadf8k91ssZIdqKqVZ6buUEvhYsOXOQsDg8FBB3m4GC1YqHeab2ezdIPLIdP3 Jyel/wpgF2Qo24/zJrMXTWnpXZAk/hHf6cj6ynX/nc/1u5C10iZMHnJX9fqcF0gZwJsH 6ePtO3M+s4Ne6wlvqKUDWaxQaGUh4k55HrED3yiU4ALRdDWF4vEWggCGNZcM3ieEH5Vw B0Bw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:subject:in-reply-to:message-id :references:mime-version; bh=cbcTBy1vA4K8807YqFE77gALyKa6C+0LW6TM1xrw0wQ=; b=7cl9yX5yZKTKQyGRIJQ+NM30OZ/zs3Pk0zo6w1QPJzXQnvmDlipqRdjGdVqPlLWLkx KH0RGmgoX15yLXPjzksgB14PDw3fj6kaJtPnt5DEh+wfupogLM+Ner62bUomlesu2CnK l8UfPrBBStuJmxS7pHZfjcxKntS5gCfW9GpNKlkRFVSEZACgSU39fKCG0TkQjYTxfx5d 1QpPO9OTCxctFuEvJMU5klYxNhZ5IO5DOHCQSD0EFgoZU6hQ3G+RYun84x+Th7XSe/+i otRXlO4jmNqezc0MBwBYmDcLEQ6xAyc2HF/BMeQBB2rTzkEAHCfQP8PKyivqHNoiLvV6 lodg== X-Gm-Message-State: AOAM531/rk+coF0HB497KG9LlPgqAcWPT9BWGpTLLxy8NIVUT/ashDOh IMAV5CRAQ1uVlOsUkpQ7cdFCP4TTIid9mA== X-Google-Smtp-Source: ABdhPJzFQknBCBov4FTXoNrHSILPujlT6XTsNRCFfHP68N4WK3es3I+PylAt+SMdLThqma8VIm+BsQ== X-Received: by 2002:adf:e68b:: with SMTP id r11mr3034329wrm.568.1642062896112; Thu, 13 Jan 2022 00:34:56 -0800 (PST) Received: from [192.168.178.26] (dslb-092-078-031-232.092.078.pools.vodafone-ip.de. [92.78.31.232]) by smtp.gmail.com with ESMTPSA id m35sm11976554wms.1.2022.01.13.00.34.55 for (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 13 Jan 2022 00:34:55 -0800 (PST) Date: Thu, 13 Jan 2022 08:32:26 +0000 (UTC) From: Roderick To: FreeBSD Questions List Subject: Re: dd and mbr In-Reply-To: <20220112214107.GI61872@eureka.lemis.com> Message-ID: <5ad46ace-9241-bbba-df61-162b3ffe461b@gmail.com> References: <4af920fc-eff1-a92e-d36e-1ba97079864c@gmail.com> <20220112010402.GG61872@eureka.lemis.com> <20220112214107.GI61872@eureka.lemis.com> List-Id: User questions List-Archive: https://lists.freebsd.org/archives/freebsd-questions List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-questions@freebsd.org X-BeenThere: freebsd-questions@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed X-Rspamd-Queue-Id: 4JZHmd02jhz3j3j X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=gmail.com header.s=20210112 header.b=ggzeol18; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (mx1.freebsd.org: domain of hruodr@gmail.com designates 2a00:1450:4864:20::42f as permitted sender) smtp.mailfrom=hruodr@gmail.com X-Spamd-Result: default: False [-2.42 / 15.00]; RCVD_VIA_SMTP_AUTH(0.00)[]; FREEMAIL_FROM(0.00)[gmail.com]; R_SPF_ALLOW(-0.20)[+ip6:2a00:1450:4000::/36]; RCVD_COUNT_THREE(0.00)[3]; TO_DN_ALL(0.00)[]; DKIM_TRACE(0.00)[gmail.com:+]; DMARC_POLICY_ALLOW(-0.50)[gmail.com,none]; NEURAL_HAM_SHORT(-0.77)[-0.772]; RECEIVED_SPAMHAUS_PBL(0.00)[92.78.31.232:received]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; FREEMAIL_ENVFROM(0.00)[gmail.com]; ASN(0.00)[asn:15169, ipnet:2a00:1450::/32, country:US]; MID_RHS_MATCH_FROM(0.00)[]; DWL_DNSWL_NONE(0.00)[gmail.com:dkim]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; R_DKIM_ALLOW(-0.20)[gmail.com:s=20210112]; FROM_HAS_DN(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; PREVIOUSLY_DELIVERED(0.00)[questions@freebsd.org]; RCPT_COUNT_ONE(0.00)[1]; NEURAL_SPAM_LONG(0.35)[0.353]; RCVD_IN_DNSWL_NONE(0.00)[2a00:1450:4864:20::42f:from]; RCVD_TLS_ALL(0.00)[] X-ThisMailContainsUnwantedMimeParts: N On Thu, 13 Jan 2022, Greg 'groggy' Lehey wrote: > As others have suggested, use bs=64k. Otherwise dd does an IO for > every single sector. The speedup is really in the order of 100x. I used bs=1m. I hope that was also OK. In any case faster than without it.