Red Hat Bugzilla – Bug 150787
Cannot create raid device manually because of missing device
Last modified: 2007-11-30 17:07:16 EST
Because udev only creates required devices, I cannot create a new
raid, reason: device is missing
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Install RHEL4, but leave some space on the disks free
2. create partition on each disk, type fd
3. reboot to activate partitions, needed because of:
WARNING: Re-reading the partition table failed with error 16: Device
or resource busy.
4. try to create raid:
# mdadm --create /dev/md2 --level 1 --raid-devices 2 /dev/sd[ab]5
Actual Results: mdadm: error opening /dev/md2: No such file or directory
Expected Results: Working
# ll /dev/md*
brw-rw---- 1 root disk 9, 0 Mar 10 17:14 /dev/md0
brw-rw---- 1 root disk 9, 1 Mar 10 17:14 /dev/md1
# mknod /dev/md2 b 9 2 && mdadm --create /dev/md2 --level 1
--raid-devices 2 /dev/sd[ab]5
mdadm: array /dev/md2 started.
Perhaps mdadm should get smarter and create missing devices (or
request creation using udev).
BTW: one can extend mknod also to understand "mdX" automagically like
already on "hdX".
This isn't a bug. The mdadm program, as per the upstream developer's wishes,
does not currenly automatically create device nodes. In order to have mdadm
create the device node as part of the array creation process, the option
--auto=yes may be passed on the create command line and it will do as you are
expecting. Further details of the --auto option can be found in the man page