I'm lucky, I reproduced it again and I ran the command udevadm monitor > monitor before test. I'll put it in as an attachment. I found there is a not whole message in the last line. Xiao ----- Original Message ----- > From: "Xiao Ni" <xni@xxxxxxxxxx> > To: "NeilBrown" <neilb@xxxxxxx> > Cc: linux-raid@xxxxxxxxxxxxxxx > Sent: Thursday, March 26, 2015 3:36:35 PM > Subject: Re: /dev/md0 can't be created > > Hi Neil > > I can reproduce it now. Do you want me to run udevadm monitor before the > test? > And I checked the /var/log/messages, it show the information: > > Oct 20 19:59:59 ibm-z10-25 kernel: md: bind<dm-2> > Oct 20 19:59:59 ibm-z10-25 kernel: md: bind<dm-3> > Oct 20 19:59:59 ibm-z10-25 kernel: md: bind<dm-4> > Oct 20 19:59:59 ibm-z10-25 kernel: md: bind<dm-5> > Oct 20 19:59:59 ibm-z10-25 kernel: md: bind<dm-6> > Oct 20 19:59:59 ibm-z10-25 kernel: md: bind<dm-7> > Oct 20 19:59:59 ibm-z10-25 kernel: md: bind<dm-9> > Oct 20 19:59:59 ibm-z10-25 kernel: md: bind<dm-8> > Oct 20 19:59:59 ibm-z10-25 kernel: md/raid:md0: device dm-7 operational as > raid disk 5 > Oct 20 19:59:59 ibm-z10-25 kernel: md/raid:md0: device dm-6 operational as > raid disk 4 > Oct 20 19:59:59 ibm-z10-25 kernel: md/raid:md0: device dm-5 operational as > raid disk 3 > Oct 20 19:59:59 ibm-z10-25 kernel: md/raid:md0: device dm-4 operational as > raid disk 2 > Oct 20 19:59:59 ibm-z10-25 kernel: md/raid:md0: device dm-3 operational as > raid disk 1 > Oct 20 19:59:59 ibm-z10-25 kernel: md/raid:md0: device dm-2 operational as > raid disk 0 > Oct 20 19:59:59 ibm-z10-25 kernel: md/raid:md0: allocated 0kB > Oct 20 19:59:59 ibm-z10-25 kernel: md/raid:md0: raid level 5 active with 6 > out of 7 devices, algorithm 2 > Oct 20 19:59:59 ibm-z10-25 kernel: md/raid456: discard support disabled due > to uncertainty. > Oct 20 19:59:59 ibm-z10-25 kernel: Set > raid456.devices_handle_discard_safely=Y to override. > Oct 20 19:59:59 ibm-z10-25 kernel: md0: detected capacity change from 0 to > 1881145344 > Oct 20 19:59:59 ibm-z10-25 kernel: md: recovery of RAID array md0 > Oct 20 19:59:59 ibm-z10-25 kernel: md: minimum _guaranteed_ speed: 1000 > KB/sec/disk. > Oct 20 19:59:59 ibm-z10-25 kernel: md: using maximum available idle IO > bandwidth (but not more than 200000 KB/sec) for recovery. > Oct 20 19:59:59 ibm-z10-25 kernel: md: using 128k window, over a total of > 306176k. > Oct 20 19:59:59 ibm-z10-25 systemd-udevd: inotify_add_watch(7, /dev/md0, 10) > failed: No such file or directory > > Xiao > > ----- Original Message ----- > > From: "NeilBrown" <neilb@xxxxxxx> > > To: "Xiao Ni" <xni@xxxxxxxxxx> > > Cc: linux-raid@xxxxxxxxxxxxxxx > > Sent: Wednesday, March 25, 2015 2:35:29 PM > > Subject: Re: /dev/md0 can't be created > > > > On Wed, 25 Mar 2015 02:15:34 -0400 (EDT) Xiao Ni <xni@xxxxxxxxxx> wrote: > > > > > Hi all > > > > > > I have encountered so many times, the raid device is created > > > successfully, but the directory > > > /dev/md0 can't be created. It can't reproduce 100%. > > > > > > [root@intel-sugarbay-do-01 create_assemble]# cat /proc/mdstat > > > Personalities : [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] > > > md0 : active raid10 loop7[7](S) loop6[6] loop5[5] loop4[4] loop3[3] > > > loop2[2] loop1[1] loop0[0] > > > 1788416 blocks super 1.2 512K chunks 2 near-copies [7/7] [UUUUUUU] > > > bitmap: 0/1 pages [0KB], 65536KB chunk > > > > > > unused devices: <none> > > > [root@intel-sugarbay-do-01 create_assemble]# ls /dev/md0 > > > ls: cannot access /dev/md0: No such file or directory > > > > > > The underline devices are loop devices which are created with big > > > file. > > > > > > The kernel I used is RHEL7 (3.10.0-234.el7.x86_64.debug, mdadm - > > > v3.3.2 > > > - 21st August 2014) > > > I'll try to reproduce this with upstream kernel and mdadm. But I think it > > > shouldn't be the problem about kernel. > > > > > > What do you think I should check for this? And which tool is > > > responsible for creating the directory? Maybe > > > I can add some log to it to find the reason. > > > > > > > /dev/md0 is created by udev. > > Run > > udevadm monitor > > > > to see the events that udev is processing. When and ADD event for "md0" is > > processed, /dev/md0 should get created. > > > > NeilBrown > > > -- > 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 >
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