Originally posted by: shargus

Trying to create a new volume group using

mkvg -S -f -s 1024 -y vgoracle hdisk2

we're getting 0516-021 message about the major number is in use.

The mkvg command did not actually create a vgoracle (and thus, no device file), so we can't tell what major number it has a problem with.
So, I tried adding a "-C" to the mkvg command. This time, it created a vgoracle volume group with associated device file. The major number is 37.
As expected, trying to varyonvg vgoracle gives the "major number already in use" error.

The problem is, we cannot find any other device file with major number 37.

We even poked around in the ODM looking for it.

If we do the same mkvg, but this time specified a major number (we picked 41 at random), it works fine.

So, 1) What is mkvg colliding with? 2) If I need to specify a major number, how can I tell (in a script) which ones are available for use? 37 appears to be available here, yet mkvg (and varyonvg) choke on it.
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Originally posted by: MarkTaylor

use kdb .. then either "devsw" or "pdt *" and look for your major number in HEX .. it will be there .. I hit this last year when trying to import some VGs with specific major numbers ..

HTH
Mark Taylor
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Originally posted by: MarkTaylor

actually, pdt is the paging device tab .. so it may not be listed there, but it will be in the device switch table "devsw"
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Originally posted by: MarkTaylor

lvgenmajor command will show you the next major number available to use btw ..
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Originally posted by: cggibbo

lvlstmajor - shows a list of device major numbers not currently in use e.g.

1. lvlstmajor

34...
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Originally posted by: shargus

lvgenmajor says major number 37 is available:

.h2 # lvgenmajor vgtest
.h2 37

Yet, mkvg says it's not:

.h2 # mkvg -S -f -s 1024 -V 37 -y vgtest hdisk1
.h2 vgtest
.h2 0516-021 /usr/sbin/varyonvg: The varyonvg failed because the volume group's
.h2 major number was already used by another device.
.h2 0516-862 mkvg: Unable to create volume group.
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Originally posted by: orphy

I know you mentioned that you tried to locate the device that has the major number 37 but can you show us the output of this command?

ls -l /dev|grep 37,

Something else interesting to try would be

mkvg -S -f -s 1024 -V 40 -y vgtest hdisk1
varyoffvg vgtest
exportvg vgtest
importvg -V 37 -y vgtest hdisk1

Since it was the varyonvg that failed, I expect importvg -V 37 to fail as well but it would be a good exercise to give it a quick try.

To fix this, you might just need to open a PMR and send Support a snap so that they can look at the whole picture in order to fix this for you. Please do report back the outcome though.
Orphy
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Originally posted by: shargus

ls -l /dev/| grep 37

no files listed.

# mkvg -S -f -s 1024 -V 40 -y vgtest hdisk1

0516-372 mkvg: The chkmajor function failed.

0516-862 mkvg: Unable to create volume group.

# lvlstmajor

38..40,44...

Interesting...
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Originally posted by: shargus

kdb does say the device file is in use... (37 dec is 25 hex)
Slot address F1000100101B4280
MAJOR: 025
open: 047D26F8
close: 047D2670
read: 047D20E0
write: .nodev (0019A394)
ioctl: 047D1D98
strategy: .nodev (0019A394)
ttys: 00000000
select: .nodev (0019A394)
config: .nodev (0019A394)
print: .nodev (0019A394)
dump: .nodev (0019A394)
mpx: .nodev (0019A394)
revoke: .nodev (0019A394)
dsdptr: 00000000
selptr: 00000000
opts: 0000002A DEV_DEFINED DEV_MPSAFE
I'm not sure if I'm reading this right, but it appears device 37 has open, close, read, and ioctl handles, but no write handle?
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Originally posted by: MarkTaylor

I done quite a bit of investigation on this last year as I was migrating LUNs between VIO Servers and importing using the original major numbers and I hit issues as you have ..

You may ket a clue if you see what the kex is loaded at the open address i.e.

$ kdb
(0)> lke -s 047D26F8
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Originally posted by: shargus

lvlstmajor reports that major number 37 is available:

$ lvlstmajor

37..40,44...

yet mkvg says it's already in use:

# mkvg -S -f -s 1024 -V 37 -y vgtest hdisk1

vgtest

0516-021 /usr/sbin/varyonvg: The varyonvg failed because the volume group's

major number was already used by another device.

0516-862 mkvg: Unable to create volume group.

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Originally posted by: shargus

The problem was with Hitachi's HDLM.

HDLM creates it's own special devices. The device files were already in /dev and in the ODM, but not in the kernel. At some point, HDLM recreated the kernel device entries with new major numbers, but did not correct the ODM and the device files. At that point, the major numbers got out of sync and things went downhill from there.

The fix is to remove and re-install HDLM.
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Originally posted by: PrabhanjanG

A simple reboot the node resolved a similar issue I was facing. 

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