From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail1.merlins.org (magic.merlins.org [209.81.13.136]) (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 CDDFF35AC2B for ; Wed, 8 Apr 2026 23:10:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.81.13.136 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775689809; cv=none; b=iTfdIRDTLk0cfhYo/WxdNj95wDbECF3fz3XlFjvj6udrPfp38atZwxvUIOnkwAPURT5XurC4M0PcPTlgIN7wnGKrlN9/GEti0QjdFcPJznzJE/jBwmJ527X0yHsgbdUfiFQslafcJxxwo2oLBH2eckx73C29ZKm1zpr7oojcuLE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775689809; c=relaxed/simple; bh=sF/4w219LH7f/vcwffYwtFYGOmpowMQVBXQwZezvf58=; h=Date:From:To:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition; b=DTL679WTOPFp1jkeXpWm7AFOFYV4i/RXAaIhucOJDaprBAAhCEzQQVflPbCesPZcvQhOpBd7BST7afNQKucRkRv4A1DgVmZH7D1h4YGYtZd/NpmAFs3apIzbc2wIS/j9+qioHK8tvdwdqpEqWMK8/9QC4KEzlpLUlWO+aQv0Wq4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=merlins.org; spf=pass smtp.mailfrom=merlins.org; dkim=pass (2048-bit key) header.d=merlins.org header.i=@merlins.org header.b=qE7ODwz/; arc=none smtp.client-ip=209.81.13.136 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=merlins.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=merlins.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=merlins.org header.i=@merlins.org header.b="qE7ODwz/" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=merlins.org ; s=20251023; h=Content-Type:MIME-Version:Message-ID:Subject:To:From:Date: Sender:Reply-To:Cc:Content-Transfer-Encoding:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: In-Reply-To:References:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=g8Kn21AnwMXLiRVa9ZTZL66Py5a49KS3rwTXNL/TZ6U=; b=qE7ODwz//3e0Gfq1ZvQSPEh1BK GVjiWL5vbRbrVu4XqT/oMxyxNNhrkrPVQkBaElJbaABejZFYl6KrHiVjXJoE9sMqCiRPxXKgyQTLZ P/vte4nBbSH1qARrWQGdHO2GQefZfuINoEPQcpa6cBFDrB/8zzwYktYTW0vEdNTMRzIO52uKRz+Ue in3Z3Brg5v152jcup3aWsrNfo4zR+rjRA1F1JfLMW7tKxWjczdRwzQKYjp/VI7OkinDEDTsNjDRNv 9XbCkOAJVggDTdQc9mVnaLkqcuu7kwYBC9F1VBaVKCaVHqfpdvtnsMIkFAN+sus7tPgxg12CU5OdG fAJLQKYw==; Received: from merlin by mail1.merlins.org with local (Exim 4.98.2 #2) id 1wAc2B-0000000AVCd-0q41 by authid ; Wed, 08 Apr 2026 16:10:07 -0700 Date: Wed, 8 Apr 2026 16:10:07 -0700 From: Marc MERLIN To: linux-btrfs@vger.kernel.org Subject: What's the status of BTRFS RST instead of linux md raid5? Message-ID: Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Sysadmin: BOFH X-URL: http://marc.merlins.org/ X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: marc@merlins.org So, I'm aware that the built in btrfs raid5 support that's been there for 10-ish years is not recommended due to hard to fix or unfixable flaws. But with raid5, once I have a checksum mismatch, btrfs could easily run all combinations of the blocks to find out which one can be removed to yield a correct checksum for that data block, but obviously those layers don't talk, so nothing happens outside of btrfs telling me the checksum is bad, and there is no good way to rebuild anything, especially when it's bit rot in a read only snapshot where I cannot reasonably delete or rewrite the file without some surgery. Gemini tells me that RST with the future that fixes this so I can use raid5 or raid6 directly in btrfs where everything talks to one another, but I can't find good docs or status on RST. Even this list has very little about RST outside of some old patches. So, is RST kind of ready and documented, or is it still very experimental and "read the source, luke" ? Thanks, Marc -- "A mouse is a device used to point at the xterm you want to type in" - A.S.R. Home page: http://marc.merlins.org/