Disk partitions detected but /dev nodes not created [solved]

All other questions
l4dvecndc1
Posts: 2
Joined: 18 Jun 2015, 15:00

Disk partitions detected but /dev nodes not created [solved]

Postby l4dvecndc1 » 18 Jun 2015, 15:28

Code: Select all

SRC 4.5.3 on an Nvidia Nforce 4 motherboard with 8 hard disks.
The kernel sees the partitions on all hard disks :

# dmesg -t | grep '< sd' | sort
 sda: sda1 sda2 sda3 sda4 < sda5 >
 sdb: sdb1 sdb2 sdb3 sdb4 < sdb5 sdb6 sdb7 >
 sdc: sdc1 sdc2 sdc3 sdc4 < sdc5 >
 sdd: sdd1 sdd2 sdd3 sdd4 < sdd5 >
 sde: sde1 sde2 sde3 sde4 < sde5 >
 sdj: sdj1 sdj2 sdj3 sdj4 < sdj5 >
 sdk: sdk1 sdk2 sdk3 sdk4 < sdk5 >
 sdl: sdl1 sdl2 sdl3 sdl4 < sdl5 sdl6 >

but the per-partition /dev nodes for sde, sdj and sdk are missing :

# ls -l /dev/sd*
brw-rw---- 1 root disk 8,   0 Jun 18 11:50 /dev/sda
brw-rw---- 1 root disk 8,   1 Jun 18 11:50 /dev/sda1
brw-rw---- 1 root disk 8,   2 Jun 18 11:50 /dev/sda2
brw-rw---- 1 root disk 8,   3 Jun 18 11:50 /dev/sda3
brw-rw---- 1 root disk 8,   4 Jun 18 11:50 /dev/sda4
brw-rw---- 1 root disk 8,   5 Jun 18 11:50 /dev/sda5
brw-rw---- 1 root disk 8,  16 Jun 18 11:50 /dev/sdb
brw-rw---- 1 root disk 8,  17 Jun 18 11:50 /dev/sdb1
brw-rw---- 1 root disk 8,  18 Jun 18 11:50 /dev/sdb2
brw-rw---- 1 root disk 8,  19 Jun 18 11:50 /dev/sdb3
brw-rw---- 1 root disk 8,  20 Jun 18 11:50 /dev/sdb4
brw-rw---- 1 root disk 8,  21 Jun 18 11:50 /dev/sdb5
brw-rw---- 1 root disk 8,  22 Jun 18 11:50 /dev/sdb6
brw-rw---- 1 root disk 8,  23 Jun 18 11:50 /dev/sdb7
brw-rw---- 1 root disk 8,  32 Jun 18 11:50 /dev/sdc
brw-rw---- 1 root disk 8,  33 Jun 18 11:50 /dev/sdc1
brw-rw---- 1 root disk 8,  34 Jun 18 11:50 /dev/sdc2
brw-rw---- 1 root disk 8,  35 Jun 18 11:50 /dev/sdc3
brw-rw---- 1 root disk 8,  36 Jun 18 11:50 /dev/sdc4
brw-rw---- 1 root disk 8,  37 Jun 18 11:50 /dev/sdc5
brw-rw---- 1 root disk 8,  48 Jun 18 11:50 /dev/sdd
brw-rw---- 1 root disk 8,  49 Jun 18 11:50 /dev/sdd1
brw-rw---- 1 root disk 8,  50 Jun 18 11:50 /dev/sdd2
brw-rw---- 1 root disk 8,  51 Jun 18 11:50 /dev/sdd3
brw-rw---- 1 root disk 8,  52 Jun 18 11:50 /dev/sdd4
brw-rw---- 1 root disk 8,  53 Jun 18 11:50 /dev/sdd5
brw-rw---- 1 root disk 8,  64 Jun 18 11:50 /dev/sde
brw-rw---- 1 root disk 8,  80 Jun 18 11:50 /dev/sdf
brw-rw---- 1 root disk 8,  96 Jun 18 11:50 /dev/sdg
brw-rw---- 1 root disk 8, 112 Jun 18 11:50 /dev/sdh
brw-rw---- 1 root disk 8, 128 Jun 18 11:50 /dev/sdi
brw-rw---- 1 root disk 8, 144 Jun 18 11:50 /dev/sdj
brw-rw---- 1 root disk 8, 160 Jun 18 11:50 /dev/sdk
brw-rw---- 1 root disk 8, 176 Jun 18 11:50 /dev/sdl
brw-rw---- 1 root disk 8, 177 Jun 18 11:50 /dev/sdl1
brw-rw---- 1 root disk 8, 178 Jun 18 11:50 /dev/sdl2
brw-rw---- 1 root disk 8, 179 Jun 18 11:50 /dev/sdl3
brw-rw---- 1 root disk 8, 180 Jun 18 11:50 /dev/sdl4
brw-rw---- 1 root disk 8, 181 Jun 18 11:50 /dev/sdl5
brw-rw---- 1 root disk 8, 182 Jun 18 11:50 /dev/sdl6

Why does that happen and what can I do about it ? Thanks in advance.

gernot
Posts: 1127
Joined: 07 Apr 2010, 16:19

Re: Disk partitions detected but /dev nodes not created

Postby gernot » 18 Jun 2015, 15:55

So what...never had this.

what gives "cat /proc/partitions"
and "blkid"

Is there a comment about this in the dmesg output or syslog?

Gernot

l4dvecndc1
Posts: 2
Joined: 18 Jun 2015, 15:00

Re: Disk partitions detected but /dev nodes not created

Postby l4dvecndc1 » 23 Jun 2015, 18:38

gernot wrote:So what...never had this.

what gives "cat /proc/partitions"
and "blkid"

Is there a comment about this in the dmesg output or syslog?


Good idea to make me look at blkid & /proc/partitions. Turns out
that /dev/sd{e,j,k} had once been part of a RAID-5 array and
still had an MD 0.90 superblock saying so. On boot, the system
detected the superblocks and decided to ignore those disks'
partition tables.

The fix was :

Code: Select all

mdadm --stop the spurious MD arrays
for f in /dev/sd{e,j,k}; do
  mdadm --zero-superblock $f
  mdadm -E $f   # confirm that not an array component any more
  fdisk -l $f   # re-read the partition table
  sfdisk -R $f  # make the kernel aware of the "new" partition table
done


Those disks have had that MD superblock for years and I had
never run into this.


Return to “Other”

Who is online

Users browsing this forum: No registered users and 1 guest