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
