VG creation error

[Brando Sumayao]

Is there a max on how many volume groups can be created. I was creating a volume group named 'vg08' and I was getting an error stating the ff:

vgcreate: Cannot open the control file "dev/vg08/group":
No such device

Please help and thanks!

Brando

[Patrick Wallek]

There is a limit to the number of VGs you can create. It is contolled by the max_vg kernel parameter.

When you are creating the VG are you doing it from the command line? If so did you create the /dev/vg08 directory and the /dev/vg08/group file?

If not, you need to do that.

# mkdir /dev/vg08
# mknod /dev/vg08/group c 64 0x0?0000

Where the ? is a unique number among your other vg??/group files. An easy way to see all the group files:

# ls -l /dev/vg*/group

[harry d brown jr]

Did you forget to put the "/" in front of "/dev/vg08" ??

live free or die
harry

[Jim Turner · Accepted solution]

Hi Brando,

Are you using cmd line or SAM? If cmd line, did you mknod the group file before your vgcreate?

And yes, there is a limit set by the kernel parm "maxvgs". I think the default is 10.

Cheers,
Jim

[Uday_S_Ankolekar]

Hi,

Check the group file by
ls -l /dev/vg*/group and notedown the used numbers in 0x0n0000
then mkdir /dev/vg08
mknod /dev/vg08/group c 64 0x0n0000
the n is the unique number
Parameter maxvgs in kernel controls max number of vgs.

Goodluck
-USA..

[Brando Sumayao]

Hi all,

I was creating addt'l VG's using SAM. Is this a problem?

[harry d brown jr]

Not at all, what is your kernel parameter maxvgs?? If it is less than 8, bump it up to 16!

and in my opinion, 8 vg's is a lot of vg's!

live free or die
harry

[Bernie Vande Griend]

Yes, there is a kernel parameter called maxvgs which determines how many volume groups you can have.

The error you are getting seems to be something else though. How are you creating it? sam?
Try creating it from the command line
mkdir /dev/vg08
mknod /dev/vg08/group c 64 0x080000 (this last number needs to be unique amongst all your volume groups)
vgcreate /dev/vg08 /dev/dsk/c?t?d?

The error suggests that you have an issue with the create of the group file.

[Darrell Allen]

Hi Brando,

I got the same error yesterday trying to create vg99 for a test. I always choose the minor number to match the vgXX number but that was my problem.

This failed:
mknod /dev/vg99/group c 64 0x990000

This worked:
mknod /dev/vg99/group c 64 0x040000

I don't have move VGs than were allowed. It just didn't like that high a minor number.

Darrell

[Deshpande Prashant]

HI
Check the kernel parameter "maxvgs" that limits the maximum number of VG in system.

Thanks.
Prashant.

[Sanjay_6]

Hi Brado,

If you are manually creating a vg you have to proceed like this,

mkdir /dev/vg_name
mknod /dev/vg_name/group c 64 0x0n0000
(here n=1,2,3,.... and is unique. Check ll /dev/*/group to find a unique no for n)
pvcreate -f /dev/rdsk/cxtydz
vgcreate /dev/vg_name /dev/dsk/cxtydz

Take a look at the threads below for more help,

http://us-support.external.hp.com/cki/bin/doc.pl/sid=8de884330c95e8ab88/screen=ckiDisplayDocument?docId=200000052659889

http://docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B2355-90742/B2355-90742_top.html&con=/hpux/onlinedocs/B2355-90742/00/00/48-con.html&toc=/hpux/onlinedocs/B2355-90742/00/00/48-toc.html&searchterms=vgcreate%20&queryid=20011113-131037

Hope this helps.

Regds

[Darrell Allen]

Hi again,

I didn't explicitly say it in my answer but as others have said, be sure the minor number is unique.

In my example, 0x04000 was not used by another VG.

Darrell