On Tue, Jun 5, 2018 at 7:34 PM, Hans Deragon <hans@xxxxxxxxxxx> wrote: > Greetings, > > Under Linux Kernel 4.4.0-127-generic, Ubuntu 16.04 LTS Xenial Xerus, I > successfully created a healthy raid10 using 4x4Tib, LVM2 and ext4. > > When I boot into a USB keyfob installed with Ubuntu 18.04 LTS Bionic > Beaver, Linux Kernel 4.15.0-20-generic #21-Ubuntu SMP, the system cannot > find the LVM2 physical volume. > > Under Ubuntu 18.04 (USB keyfob), I run: > > $ apt install mdadm > ... > $ mdadm --verbose --assemble /dev/md0 # Works! > $ cat /proc/mdstat # Shows raid. > Personalities : [raid10] [linear] [multipath] [raid0] [raid1] [raid6] > [raid5] [raid4] > md0 : active raid10 sdh[0] sdb[1] sdc[2] sdd[3] > 7813774336 blocks super 1.2 512K chunks 2 near-copies [4/4] [UUUU] > bitmap: 0/59 pages [0KB], 65536KB chunk > > $ pvscan # Shows nothing! > $ pvscan is an LVM command. While LVM numbered RAID levels use the kernel md driver, LVM uses its own on-disk metadata format separate from mdadm's metadata format. > > Why can't pvscan find the physical volume? Remember, this is a %100 > healthy working RAID10. If I remove the USB keyfob and reboot into my > Ubuntu 16.04 LTS system, the whole drive (ext4) gets automatically > mounted properly, all the time without any errors. It works flawlessly > under Linux Kernel 4.4.0-127-generic, but not with Linux Kernel > 4.15.0-20-generic #21. You haven't provided enough information. You're talking about mdadm in one case and pvscan in another case. Maybe you could try 'sudo blkid' under both OS's and while you're at it capture dmesg for both OS's and compare why it's detected in one case and not the other. > > On the web, I find only people having defective RAIDs when pvscan > returns nothing. Is there a way to force pvscan/LVM2 to consider /dev/md0? No. They're not the same thing, they're not interchangeable. -- Chris Murphy -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
