From nobody Thu Jul 03 01:09:04 2025 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 4bXdvh1YVBz60vjg for ; Thu, 03 Jul 2025 01:09:20 +0000 (UTC) (envelope-from dpchrist@holgerdanske.com) Received: from holgerdanske.com (holgerdanske.com [IPv6:2001:470:0:19b::b869:801b]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "holgerdanske.com", Issuer "R10" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4bXdvf5pzJz3nmy for ; Thu, 03 Jul 2025 01:09:18 +0000 (UTC) (envelope-from dpchrist@holgerdanske.com) Authentication-Results: mx1.freebsd.org; dkim=pass header.d=holgerdanske.com header.s=nov-20210719-112354 header.b=QkB9nyY1; spf=pass (mx1.freebsd.org: domain of dpchrist@holgerdanske.com designates 2001:470:0:19b::b869:801b as permitted sender) smtp.mailfrom=dpchrist@holgerdanske.com; dmarc=pass (policy=none) header.from=holgerdanske.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=holgerdanske.com; s=nov-20210719-112354; t=1751504945; bh=8kbMVWYIGy7+A1AlOrTtDwOEBwOje8k6XPkM+Nc2jwg=; h=Received:Message-ID:Date:MIME-Version:User-Agent:Subject:To: References:Content-Language:From:In-Reply-To:Content-Type: Content-Transfer-Encoding; b=QkB9nyY1LqCXhLOqnE7mzpf5cv3+F0yW40U8YOJa1ZvYEQGG1NkH90WFBY4czAYzm +A6dg1/5e28Nro9WtiK3UAEBZVojWUSQOtFUybJmlW4QIdvfvuICPtO/ld9aSW8YSf a3CQ4hTx8V0TyQmMXbiyZUnl/OYGu1jGPWkjKiNj1BIsdptMSNF4Rn80r3+HIFBLs+ 487PHg/TZ0kERzU5ZmWgRjbqIReb4ZjpdL0JNOTkwq6bK4HzlKQONr3+AEreQcXqQu iGP6VoyEzrKWCYeE5M9GBjEGygW0jLvScr6Z9wgHR7BhEFxfqyCDy2pauHT4a8FaLj Khz/lxBaEe3G6jYZazrsQN+ibSUpQor1gP0aJyyik3o1i7oFuUTrCidiP6Qs+XvwQi f1U3qwLczPyCKyMJpXHBAJsjoNWesVC0OJWL0hP7AbeZ6ZRnwgGRCCKddhy8vyRbEA zpaytspwX/l47DBB8yhxAkGxS+FUjyIwD7dcVwKfQkX819XGVqV6Dxz9KBEi1hoM9m jP/v4Hw4e9m7PEBDIWpkLMCoq4HQux8R747gaE/+q7KTnbu9Em6ygBFJdWqADgzrOt HEkNLR+Ajs4Wx8qNnNH9yRHNFuQu1AdZw5QTJUnQCvayUosscUbzAMdAHEryl963XJ gZGPqUMb3yPMiPGzXhC2RrxI= Received: from 99.100.19.101 (99-100-19-101.lightspeed.frokca.sbcglobal.net [99.100.19.101]) by holgerdanske.com with ESMTPSA (TLS_AES_128_GCM_SHA256:TLSv1.3:Kx=any:Au=any:Enc=AESGCM(128):Mac=AEAD) (SMTP-AUTH username dpchrist@holgerdanske.com, mechanism PLAIN) for ; Wed, 2 Jul 2025 18:09:05 -0700 Message-ID: <7994f04b-4cdb-4c57-b27a-25b60ebc3347@holgerdanske.com> Date: Wed, 2 Jul 2025 18:09:04 -0700 List-Id: User questions List-Archive: https://lists.freebsd.org/archives/freebsd-questions List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: freebsd-questions@freebsd.org Sender: owner-freebsd-questions@FreeBSD.org MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: Wiping a disk partition To: questions@freebsd.org References: <911980c8-29dc-46b2-bc47-3badda7bd03c@fjl.co.uk> Content-Language: en-US From: David Christensen In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spamd-Result: default: False [1.59 / 15.00]; NEURAL_SPAM_LONG(1.00)[1.000]; NEURAL_SPAM_MEDIUM(0.99)[0.995]; DMARC_POLICY_ALLOW(-0.50)[holgerdanske.com,none]; NEURAL_SPAM_SHORT(0.40)[0.396]; R_DKIM_ALLOW(-0.20)[holgerdanske.com:s=nov-20210719-112354]; R_SPF_ALLOW(-0.20)[+a]; ONCE_RECEIVED(0.20)[]; MIME_GOOD(-0.10)[text/plain]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCVD_COUNT_ONE(0.00)[1]; ASN(0.00)[asn:6939, ipnet:2001:470::/32, country:US]; MIME_TRACE(0.00)[0:+]; ARC_NA(0.00)[]; MLMMJ_DEST(0.00)[questions@freebsd.org]; RCPT_COUNT_ONE(0.00)[1]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_TLS_ALL(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; TO_DN_NONE(0.00)[]; PREVIOUSLY_DELIVERED(0.00)[questions@freebsd.org]; DKIM_TRACE(0.00)[holgerdanske.com:+] X-Rspamd-Queue-Id: 4bXdvf5pzJz3nmy X-Spamd-Bar: + On 7/2/25 01:18, Odhiambo Washington wrote: > My question was "What is the fastest way to wipe all data on /dev/ada1p2?" > It looks like delete, wipe, and erase all have different meanings here. > I should have explained that "rm -rf" would take a long time, so I needed a > faster command. > I didn't even want a secure erase, just the deletion. > I concluded that there is no straight answer to my question. I tend to think of "remove" in terms of file system metadata only -- e.g. rm(1). I tend to think of "erase" in terms of file system data and metadata -- e.g. shred(1). But, journals, copy-on-write, snapshots, wear leveling, etc., can defeat true destruction of data if the software tool and/or storage API/DDI stack are not specified designed for such. Research and verification would be required. I tend to use "wipe" for entire drives -- security erase if available, shred(1) or dd(1) /dev/zero if not. If rm(1) is too slow because you have a huge number of small files and if you do not care about leftover data on disk, the only tool I can think of that might be faster would be newfs(8). > What I ended up doing was > dd if=/dev/ada1 of=/dev/ada2 bs=1g status=progress > The 2nd disk is a replica of the 1st disk, and I use it only for creating a > backup of the first disk. I assume you mean (?): dd if=/dev/ada0 of=/dev/ada1 bs=1g status=progress That should work if you boot from ada0p2 into single-user mode, ada0p2 is mounted read-only, and ada1p2 not mounted. But, if both drives are installed (such as to recover files), you might have problems if fstab(5), etc., uses UUID's. David