From patchwork Thu Oct 26 17:41:52 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin Wilck X-Patchwork-Id: 13437773 X-Patchwork-Delegate: christophe.varoqui@free.fr Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 01C983A280 for ; Thu, 26 Oct 2023 17:42:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="eVX8uaRA" Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 923BE1FD99; Thu, 26 Oct 2023 17:42:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1698342152; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BqJQ7XYjSFPXhy+SoeL5KJNRDAarnTYDkzmkWBWDYrA=; b=eVX8uaRAmlIgBoCUhdyIXk83zpk6bBqTKBFYDvdUmd9zlwV5F9DrI2hXDY6DyZVPvcJLdb iygjB6fFjRJRIuT3+u11lb2gasAOgp4mnexczLycNtsWdUraPqCjIIW6Zxi3H7tixZedzn x0akkxyJCSoqeoHFUJzFGb5KghZW9QE= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 59B601358F; Thu, 26 Oct 2023 17:42:32 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id ABpUFAilOmVGPgAAMHmgww (envelope-from ); Thu, 26 Oct 2023 17:42:32 +0000 From: mwilck@suse.com To: Christophe Varoqui , Benjamin Marzinski Cc: dm-devel@lists.linux.dev, Martin Wilck , Xose Vazquez Perez Subject: [PATCH v2 13/14] README.md: Extend the section about NVMe Date: Thu, 26 Oct 2023 19:41:52 +0200 Message-ID: <20231026174153.1133-14-mwilck@suse.com> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231026174153.1133-1-mwilck@suse.com> References: <20231026174153.1133-1-mwilck@suse.com> Precedence: bulk X-Mailing-List: dm-devel@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Martin Wilck Signed-off-by: Martin Wilck Cc: Xose Vazquez Perez Reviewed-by: Benjamin Marzinski --- README.md | 30 ++++++++++++++++++++---------- 1 file changed, 20 insertions(+), 10 deletions(-) diff --git a/README.md b/README.md index b2ed1f2..2fb423b 100644 --- a/README.md +++ b/README.md @@ -273,15 +273,25 @@ To enable ALUA, the following options should be changed: NVMe ==== -To use Device Mapper/multipath-tools with NVMe devices, -if the Native NVMe Multipath subsystem is enabled -( "Y" in `/sys/module/nvme_core/parameters/multipath` ), -it has to be disabled: -`echo "options nvme_core multipath=N" > /etc/modprobe.d/01-nvme_core-mp.conf`, -regenerate the initramfs (`dracut -f` or `update-initramfs`) and reboot. +Using dm-multipath with NVMe +---------------------------- -Check that it is disabled(N) with: -`cat /sys/module/nvme_core/parameters/multipath` -or -`systool -m nvme_core -A multipath` +NVMe multipath is natively supported by the Linux kernel. If for some reason +you prefer using device mapper multipath with NVMe devices, +you need to disable native multipathing first: + + echo "options nvme_core multipath=N" > /etc/modprobe.d/01-nvme_core-mp.conf + +Afterwards, regenerate the initramfs (`dracut -f` or `update-initramfs`) and reboot. + +Using multipath-tools with native NVMe multipath +------------------------------------------------ + +If native NVMe multipathing is enabled, you can still use multipath-tools +for displaying the topology and some other information about native NVMe +multipath setups. This feature is disabled by default. To enable it, set +`enable_foreign nvme` in the `defaults` section of `multipath.conf`. +Commands like `multipath -ll` will then display information about NVMe +native multipath. This support is read-only; modifying the native multipath +configuration is not supported.