From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp161.vfemail.net (smtp161.vfemail.net [146.59.185.161]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BE7AEA937 for ; Tue, 3 Jun 2025 01:12:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=146.59.185.161 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748913127; cv=none; b=JPx2DZ0n+vUuBkw9uCeOwKacyM00ouD3ECVmZwHZ1X6on7+DYsAORXSCANEr7BCPLzoXjy5L4hzEXPay+En98qSflHAIVvwJ6kMZBBcuxn/DCftHp7mRrKYRdydlQn+/Ki3kwfV6Z14hQQas2y2LzpTrqYKUBiwwDAutQmYF1cI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748913127; c=relaxed/simple; bh=ScoRkzfWxwKPIKnrJDTp2bupEd2tmJxoop3VVwf7i34=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type; b=koN1gC4YxX3x0HfWYh26xlutN/aGr4+FU3B4MvFb+v6hRXRRPyqX8Gz2oDp6BIOQh0lNPyrXinJLlzlrAY0UDw8cLvmKGrl0lSTBvfxLkbMsMs77m8GzN4uka+/0Pj02kOQKmvwymOj4/3BZLkHPWEXy0I8CHnY6jLlsRYt+XXE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=vfemail.net; spf=pass smtp.mailfrom=vfemail.net; dkim=pass (1024-bit key) header.d=vfemail.net header.i=@vfemail.net header.b=bVFSaQ36; arc=none smtp.client-ip=146.59.185.161 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=vfemail.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=vfemail.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=vfemail.net header.i=@vfemail.net header.b="bVFSaQ36" Received: (qmail 1615 invoked from network); 3 Jun 2025 01:04:05 +0000 Received: from localhost (HELO nl101-3.vfemail.net) () by smtpout.vfemail.net with SMTP; 3 Jun 2025 01:04:05 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=simple; d=vfemail.net; h=date:from :to:cc:subject:message-id:mime-version:content-type :content-transfer-encoding; s=2018; bh=ScoRkzfWxwKPIKnrJDTp2bupE d2tmJxoop3VVwf7i34=; b=bVFSaQ36BouCUAeeekcHjlQKJb63O/77YVOzKYN96 M1ySS72ziPTulBP2dz258xNfunuu5eeCHr+XvEnkPvR9YOb23NMVunLoFlykSAlN M3GnrJDlkyNhJQSJ/hrzh+7DPUFkecUj/T9CS2DGJrEm7Tdrg4LSVoux57crXGkJ UY= Received: (qmail 94987 invoked from network); 2 Jun 2025 20:05:22 -0500 Received: by simscan 1.4.0 ppid: 94928, pid: 94942, t: 0.9122s scanners:none Received: from unknown (HELO bmwxMDEudmZlbWFpbC5uZXQ=) (aGdudGt3aXNAdmZlbWFpbC5uZXQ=@MTkyLjE2OC4xLjE5Mg==) by nl101.vfemail.net with ESMTPA; 3 Jun 2025 01:05:21 -0000 Date: Mon, 2 Jun 2025 21:05:14 -0400 From: David Niklas To: Linux RAID Cc: linux-kernel@vger.kernel.org Subject: Need help increasing raid scan efficiency. Message-ID: <20250602210514.7acd5325@Zen-II-x12.niklas.com> X-Mailer: Claws Mail 4.3.0git38 (GTK 3.24.24; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-raid@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Hello, My PC suffered a rather nasty case of HW failure recently where the MB would break the CPU and RAM. I ended up with different data on different members of my RAID6 array. I wanted to scan through the drives and take some checksums of various files in an attempt to ascertain which drives took the most data corruption damage, to try and find the date that the damage started occurring (as it was unclear when exactly this began), and to try and rescue some of the data off of the good pairs. So I setup the array into read-only mode and started the array with only two of the drives. Drives 0 and 1. Then I proceeded to try and start a second pair, drives 2 and 3, so that I could scan them simultaneously. With the intent of then switching it over to 0 and 2 and 1 and 3, then 0 and 3 and 1 and 2. This failed with the error message: # mdadm --assemble -o --run /dev/md128 /dev/sdc /dev/sdd mdadm: Found some drive for array that is already active: /dev/md127 mdadm: giving up. # mdadm --detail /dev/md127 Version : 1.2 Creation Time : XXX Raid Level : raid6 Array Size : XXX Used Dev Size : XXX Raid Devices : 4 Total Devices : 2 Persistence : Superblock is persistent Intent Bitmap : Internal Update Time : XXX State : clean, degraded Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 Layout : left-symmetric Chunk Size : 512K Consistency Policy : bitmap Name : XXX UUID : XXX Events : 3826931 Number Major Minor RaidDevice State 7 9 0 0 active sync /dev/md0 - 0 0 1 removed - 0 0 2 removed 6 9 1 3 active sync /dev/md1 Any ideas as to how I can get mdadm to run the array as I requested above? I did try --force, but mdadm refused to listen. Thanks, David