From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Johnson Subject: mdraid + dm-multipath - non-dm-mulitpath boot md coexisting with dm-multi md data volume? Date: Thu, 1 Oct 2015 11:55:16 -0700 Message-ID: <560D8194.2000502@aeoncomputing.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid List-Id: linux-raid.ids Greetings, I'm looking for advice on configuring mdadm.conf to allow for the coexisting of a non dm-multipath boot/root md device and a dm-multipath configured md device data volume. The issue I am running into is that on boot mdraid assumes control of all disks with md superblocks on them before multipath starts. This appears to be due to the boot/root being md devices, multipath never gets to own the other disks in the system and then assemble on mpath devices in /dev/disk/by-id. I have tried using DEVICE declarations in mdadm.conf but so far the result is either the boot volumes don't get recognized (assemble + switchroot fails) but the data volume gets assembled with dm-multipath devices, or the boot/root md devices assemble and the dm-multipath based md devices get assembled as sd member devices and dm-multipath is disabled. Some of the DEVICE declarations I tried in mdadm.conf are below. Two on the same line or two separate lines. The non dm-mulitpath boot devices are Intel SATA SSDs on the onboard SATA ports. The dm-mulitpath RAID-10 data volume is on an external SAS HBA with valid multipath configuration. I have remade the initramfs after these changes (dracut -f). DEVICE /dev/disk/by-id/scsi-SATA_INTEL_SSD.*-.* /dev/disk/by-id/dm-uuid-.*-mpath-.* and DEVICE /dev/disk/by-id/scsi-SATA_INTEL_SSD.*-.* DEVICE /dev/disk/by-id/dm-uuid-.*-mpath-.* These examples find the SAS attached dm-multipath devices fine and assemble the mdraid volumes but the boot devices are not found or assembled. A look via rdshell shows the /dev/disk/by-id/scsi-SATA_INTEL_SSD.*-.* devices listed in the /dev/disk/by-id directory. It appears mdadm doesn't like the declaration for the SSDs and won't find them. I haven't been able to figure out why so far. Current state (/proc/mdstat) cat /proc/mdstat Personalities : [raid1] [raid10] md4 : active raid10 dm-11[3] dm-5[2] dm-7[1] dm-9[0] 584615936 blocks super 1.2 512K chunks 2 near-copies [4/4] [UUUU] bitmap: 0/5 pages [0KB], 65536KB chunk md3 : active raid1 dm-10[3] dm-2[2] dm-4[1] dm-8[0] 521792 blocks super 1.2 [4/4] [UUUU] md0 : active raid1 sdb1[1] sda1[0] 255936 blocks super 1.0 [2/2] [UU] md2 : active raid1 sdb3[1] sda3[0] 225653760 blocks super 1.1 [2/2] [UU] bitmap: 0/2 pages [0KB], 65536KB chunk md1 : active raid1 sda2[0] sdb2[1] 8380416 blocks super 1.1 [2/2] [UU] unused devices: OS: CentOS 6.6 x86_64 2.6.32-504.el6.x86_64 If anyone has suggestions of how to configure a proper set of DEVICE declarations to assemble the SATA connected member drives of the boot/root volumes without relying on the default "DEVICE partitions containers" where the multipath devices get assembled as sd devices prior to multipath starting I would appreciate the advice. Thanks, --Jeff