vgcreate: Cannot open the control file "/dev/vgsan_os/group":

[CA1477191]

Hi i am having problems using command vg create.
So far i have executed fllowing comands..

1)insf -e
2)ioscan -fnCkdisk
Output/New Disk
disk 4 255/255/0/0.4 sdisk CLAIMED DEVICE HSV110 (C)COMPAQ
/dev/dsk/c12t0d4 /dev/rdsk/c12t0d4


3)umask 022
4)pvcreate /dev/rdsk/c12t0d4

5)mkdir /dev/vgsan_os

6)ls -l /dev/*/group

root@bhluksap2:/dev/vgsan_os> ls -l /dev/*/group
crw-r----- 1 root sys 64 0x000000 Feb 19 20:06 /dev/vg00/group
crw-r--r-- 1 root sys 64 0x080000 Apr 18 12:14 /dev/vg_temp/group
crw-rw-rw- 1 root sys 64 0x040000 Feb 21 16:04 /dev/vgdev_data/group
crw-rw-rw- 1 root sys 64 0x030000 Feb 21 14:27 /dev/vgdev_os/group
crw-r--r-- 1 root sys 64 0x070000 Apr 18 13:23 /dev/vgprod_os/group
crw-r--r-- 1 root sys 64 0x090000 May 8 11:15 /dev/vgprod_os2/group
crwxrwxrwx 1 root sys 64 0x100000 May 23 11:28 /dev/vgsan_os/group
crw-rw-rw- 1 root sys 64 0x020000 Feb 20 15:37 /dev/vgtest_data/group
crw-rw-rw- 1 root sys 64 0x010000 Feb 20 15:37 /dev/vgtest_os/group


7)mknod /dev/vgsan_os/group c 64 0x100000
Output :
crw-r--r-- 1 root sys 64 0x100000 May 23 11:28 /dev/vgsan_os/group

8) vgcreate vgsan_os /dev/dsk/c12t0d4
Output :
vgcreate: Cannot open the control file "/dev/vgsan_os/group":
No such device

I have tried changing the permissions of following folder and files..
drwxrwxrwx 2 root sys 96 May 23 11:28 vgsan_os

crwxrwxrwx 1 root sys 64 0x100000 May 23 11:28 group

but no luck,

In the beginning i did made one mistake, which was i used one used minor number 0x90000. i removed the created file directory using command
rmdir /dev/vsan_os
and started creating the sile system again from beginning.
I guess this is what causing the problem somewhere.

what is proper way to remove mknod file system?

or am i doing something wrong?

[Luk Vandenbussche · Accepted solution]

Hi,

What is de kernel value maxvgs
grep maxvgs /stand/system
If no value is returned then it is the default of 10

You are using the hexadecimal value 10 => 16 in decimal.
Maxvgs must be at least 16.
But ID 5 is stil free in your case

rm /dev/vgsan_os/group
mknod /dev/vgsan_os/group c 64 0x050000

[mavrick]

Hi,

Your Vg don't have data or LV.

Try by vgexport /de/vgsan_os

This will remove the directory and mknod
entry so that you can start a fresh vg.

or
You can remove that particular mknod entry by
rm.

Select the monor number carefully


thanks..

[mavrick]

Hi,

Your Vg don't have data or LV.

Try by vgexport /dev/vgsan_os

This will remove the directory and mknod
entry so that you can start a fresh vg.

or
You can remove that particular mknod entry by
rm.

Select the monor number carefully


thanks..

[spex]

Hello,

Luk is correct: you are exceeding maxvgs. However, this is a good opportunity to increase the value of this tunable to accommodate future inclusion of additional VGs. But don't set the value too high, as system resources will be wasted.

According to maxvgs(5):

Recommended values
10-256
The value for maxvgs should be no larger than the anticipated needs of the system. Resources are reserved for the number of volume groups indicated, so setting an unnecessarily large maxvgs value on systems with limited resources is not advisable. Conversely, it does not make sense to set maxvgs to a low value since it will likely have to be raised later when a greater number of volume groups is utilized.

Under HP-UX 11iv1:
# kmtune -s maxvgs=''

Under HP-UX 11iv2:
# kctune maxvgs=''

After changing this tunable, the kernel must be recompiled and the system rebooted.

Under HP-UX 11iv3:
Parameter is obsolete; LVM handles up to 256 VGs dynamically.

PCS

[CA1477191]

Thanks guys
I ran following commands which fixed my problem.

root@bhluksap2:/dev> mknod /dev/vgsan_os/group c 64 0x050000
root@bhluksap2:/dev> vgcreate vgsan_os /dev/dsk/c12t0d4
Increased the number of physical extents per physical volume to 17919.
Volume group "/dev/vgsan_os" has been successfully created.
Volume Group configuration for /dev/vgsan_os has been saved in /etc/lvmconf/vgsan_os.conf
root@bhluksap2:/dev>