Dear CentOS users and administrators, I solved the problem! It really was multipath and it had to do with some automatic mapping probably. I maybe did reboot after I created a new partition tables on each drive, which probably wasn't very smart. Anyway, the solution was: # multipath -l ST3500630NS_9QG0P0PY dm-1 ATA ,ST3500630NS size=466G features='0' hwhandler='0' wp=rw `-+- policy='service-time 0' prio=0 status=active `- 6:0:0:0 sdf 8:80 active undef running ST3500630NS_9QG0HLRX dm-6 ATA ,ST3500630NS size=466G features='0' hwhandler='0' wp=rw `-+- policy='service-time 0' prio=0 status=active `- 4:0:0:0 sdd 8:48 active undef running ST3500630NS_9QG0H3N5 dm-3 ATA ,ST3500630NS size=466G features='0' hwhandler='0' wp=rw `-+- policy='service-time 0' prio=0 status=active `- 5:0:0:0 sde 8:64 active undef running ST3500630NS_9QG0KYMH dm-4 ATA ,ST3500630NS size=466G features='0' hwhandler='0' wp=rw `-+- policy='service-time 0' prio=0 status=active `- 3:0:0:0 sdc 8:32 active undef running ST3500630NS_9QG0KQH2 dm-5 ATA ,ST3500630NS size=466G features='0' hwhandler='0' wp=rw `-+- policy='service-time 0' prio=0 status=active `- 8:0:0:0 sdh 8:112 active undef running ST3500630NS_9QG0H3JL dm-2 ATA ,ST3500630NS size=466G features='0' hwhandler='0' wp=rw `-+- policy='service-time 0' prio=0 status=active and remove mapping one after one, or with -F all at once: # multipath -f ST3500630NS_9QG0KYMH It was then possible to: # mdadm --create /dev/md6 --assume-clean --level=5 --raid-devices=6 /dev/sd[cdefgh]1 which worked without problem... Best regards Adam Kalisz On Fri, 2017-06-30 at 02:06 +0200, adam_kalisz wrote: > Dear fellow CentOS users, > > I have never experienced this problem with hard disk management > before > and > cannot explain it to myself on any rational basis. > > The setup: > I have a workstation for testing, running latest CentOS 7.3 AMD64. I > am > evaluating oVirt and a storage-ha as part of my bachelors thesis. > I have already been running a RAID1 (mdraid, lvm2) for the system and > some oVirt 4.1 testing. Now I added 6x 500 GB platters from an old > server running Debian 8 Jessie with software RAID of a similar fashion > as well. That would unexpectably prevent the system from booting > past something like (I copied it from the working setup), I ran it > over > night, so it was actually about 16 hours: > "A start job is running for dev-mapper-vg0\x2droot.device (13s / 1min > 30s)" > > Can it be just some kind of a scan, which takes so long? The current > throughput based > on time (16 h) and capacity (3 TB) would be about 50 MBps. (Those > drives > can be pretty > slow when writing, dd showed about 30 MBps, the write cache is off.) > > This is actually repeatable. If I unplug those drives and boot again, > it > all works. > > I don't know, if it helps but before that I had two screens full of: > "dracut-initqueue[331]: Warning: dracut-initqueue timeout - starting > timeout scripts" > > Well, I proceded without this array, and after it booted I connected > the > array of 6 hard disks again. They were recognized etc. The problem is, > I > cannot do much. I can dd from and to the harddrives, I can create and > delete partitions but I cannot create an md raid array out of them, I > cannot create a physical volume or format them with a filesystem. I > even > tried overwriting all of those harddrives with zeroes, which worked > but > didn't help at all with the creation of the array afterwards. > > mdadm --create /dev/md6 --level=5 --raid-devices=6 /dev/sd[cdefgh]1 > > "mdadm: cannot open /dev/sdc1: Device or resource busy" > > with pvcreate, it seems as if there was no device, but I clearly see > it > in /dev/sdc1... > > "Device /dev/sdc1 not found (or ignored by filtering)." > > partprobe yields: > > "device-mapper: remove ioctl on ST3500630NS_9QG0P0PY1 failed: Device > or > resource busy > Warning: parted was unable to re-read the partition table on > /dev/mapper/ST3500630NS_9QG0P0PY (Device or resource busy). This > means > Linux won't know anything about the modifications you made. > device-mapper: create ioctl on ST3500630NS_9QG0P0PY1part1-mpath- > ST3500630NS_9QG0P0PY failed: Device or resource busy > device-mapper: remove ioctl on ST3500630NS_9QG0P0PY1 failed: Device or > resource busy" > > In some forums, it was suggested, dmraid (yes, the old) could be the > trouble. I eliminated this hypothesis (overwritten all with zeroes, > fakeraid was never present with these disks). Also multipathd/ > dm_multipath could be the trouble, someone suggested. The problem is, > if > I was to remove device-mapper-multipath, I would loose oVirt-engine, > because it has multipath as dependency for some reason. > > Do you have any ideas? What logs/ information should I provide if you > want to have a look into this. > > Best regards > Adam Kalisz > _______________________________________________ > CentOS mailing list > CentOS at centos.org > https://lists.centos.org/mailman/listinfo/centos