Missing partition vpathxn only as a device file entry

[Yong Huang]

On multiple Red Hat 4 boxes, after kernel upgrade (currently 
2.6.9-89.ELsmp):

# ls /dev/vpath*
/dev/vpatha  /dev/vpatha1  /dev/vpathb  /dev/vpathb1  /dev/vpathc  
/dev/vpathd  /dev/vpathe  /dev/vpathf  /dev/vpathg

Before the upgrade, we had /dev/vpath[cdefg]1, not just /dev/vpath[cdefg]. 
But tools such as fdisk indicate the partition actually exists, e.g.,

# fdisk -l /dev/vpathc

Disk /dev/vpathc: 524 MB, 524288000 bytes
17 heads, 59 sectors/track, 1020 cylinders
Units = cylinders of 1003 * 512 = 513536 bytes

      Device Boot      Start         End      Blocks   Id  System
/dev/vpathc1               1        1020      511500+  83  Linux

# partx -l /dev/vpathc
# 1:        59-  1023059 (  1023001 sectors,    523 MB)
# 2:         0-       -1 (        0 sectors,      0 MB)
# 3:         0-       -1 (        0 sectors,      0 MB)
# 4:         0-       -1 (        0 sectors,      0 MB)

# parted /dev/vpathc
...
(parted) p
Disk geometry for /dev/vpathc: 0.000-500.000 megabytes
Disk label type: msdos
Minor    Start       End     Type      Filesystem  Flags
1          0.029    499.541  primary

So it's only missing from the /dev directory. What could have caused this? 
How do we add the partition "files" back to the directory?

We use IBM sdd:

# lsmod | grep sdd
sdd_mod               375872  2
# dmesg | grep sdd
...
sdd-mod: SDD 1.6.3.0-9 2.6.9-89.ELsmp SMP  Jun 17 2009 13:48:17 (C) IBM Corp.

`sdd status' or `lsvpcfg' correctly shows 4 paths for each vpath:

# sdd status
IBMsdd status:                                             [  OK  ]
000 vpatha  ( 252,   0) 6005076801870036a0000000000002be = 6005076801870036a0000000000002be = /dev/sda /dev/sdh /dev/sdo /dev/sdv
...

`cfgvpath' only says path has already been configured.

Process /opt/IBMsdd/bin/sddsrv is up and running. We tried start_udev, 
partprobe, fdisk -> w. None helped.

Thanks for any insight. (If you decide to CC me when you reply to the 
list, that'll be perfect.)

Yong Huang
yong321 at yahoo.com