topic how to create volumegroup in HPE EVA Storage

how to create volumegroup

Franky Leeuwerck_2 — Fri, 30 Sep 2005 04:29:36 GMT

Hello,

I have a SAN ( eva3K ) with disks presenting to my unix box.

When I try to create a new volumegroup in SAM, I get this error :
No device files for the selected device were found in /dev.

Can someone tell me what is wrong ?

Thanks in advance
Franky

Re: how to create volumegroup

Uwe Zessin — Fri, 30 Sep 2005 05:35:25 GMT

SAM cannot deal with the EVA's devices - you need to use the command line.

Re: how to create volumegroup

Luk Vandenbussche — Fri, 30 Sep 2005 06:05:11 GMT

Try it manually

mkdir /dev/vgXX
mknod /dev/vg00/group c 64 0x0X0000
pvcreate -f /dev/rdsk/cxtydz
vgcreate vgXX /dev/dsk/cxtydz

Re: how to create volumegroup

Franky Leeuwerck_2 — Fri, 30 Sep 2005 06:14:09 GMT

Hi Luk,

I'm not sure about the variables in the command line solution.

Ioscan shows me the presented disk like this :
disk 4 255/255/0/0.1 sdisk CLAIMED DEVICE HSV100 HP
/dev/dsk/c15t0d1 /dev/rdsk/c15t0d1

The volume that I want to create should be /dev/vg01 .

What should I use for variables in your statements ?

Franky

Re: how to create volumegroup

Luk Vandenbussche — Fri, 30 Sep 2005 06:25:33 GMT

Franky,

Here is the exact command

mkdir /dev/vg01
mknod /dev/vg01/group c64 0x010000
pvcreate -f /dev/rdsk/c15t0d1
vgcreate vg01 /dev/dsk/c15t0d1

You should be able to create logical volumes through sam now

Re: how to create volumegroup

Franky Leeuwerck_2 — Fri, 30 Sep 2005 06:29:14 GMT

Luk,

Thanks for your further inputs.

Can you tell me why the ' 0x010000 ' ?
I need to create about 7 volumegroups.
Should I use ' 0x010000 ' for each of these.

Franky

Re: how to create volumegroup

Scott McIntosh_2 — Fri, 30 Sep 2005 06:35:09 GMT

No, the minor number in the group file for each volume group must be different.

So if I did "ll /dev/vg*/group", I should see different numbers in the first two digits of the minor number:

crw-r----- 1 root sys 64 0x000000 Oct 28 2002 /dev/vg00/group
crw-rw-rw- 1 root sys 64 0x010000 Nov 26 2002 /dev/vg01/group

Re: how to create volumegroup

Franky Leeuwerck_2 — Fri, 30 Sep 2005 06:42:28 GMT

Thanks Scott.

Can these numbers be chosen randomly, or is there a specific order ?

Franky

Re: how to create volumegroup

Luk Vandenbussche — Fri, 30 Sep 2005 07:31:48 GMT

Francky,

It is hexadecimal.
It is defined by the kernel parameter maxvgs and it must be unique for each volumegroup.

The default kernel parameter is 10

Re: how to create volumegroup

Scott McIntosh_2 — Fri, 30 Sep 2005 07:39:45 GMT

Order is not important, they just have to be unique for each volume group present on the system. This becomes a more significant question for cluster environments, for example.

So you could have 0x00..., 0x01..., and 0x06..., for example.

Thanks,
Scott
HP Support

Re: how to create volumegroup

Franky Leeuwerck_2 — Fri, 30 Sep 2005 07:45:49 GMT

Thanks for your input, Luk and Scott.
This solves my problem.

Franky :

Once a vg is created, can one easily change the physical extend size ( from 4 to 16 MB f.i. ) ?

Re: how to create volumegroup

Franky Leeuwerck_2 — Fri, 30 Sep 2005 07:48:47 GMT

Another question .
If I have multiple disks presented for a volumegroup, should I simply run the following statements for every disk to add :
pvcreate -f /dev/rdsk/cxxt0dy
vgcreate vg01 /dev/dsk/cxxt0dy

Re: how to create volumegroup

Luk Vandenbussche — Fri, 30 Sep 2005 07:50:15 GMT

Franky you have to define it when you create it

vgcreate -s 16 /dev/vg01 /dev/dsk/c15t0d1

So repeat my steps above with this option.

Don't forget the following first

vgchange -a n vg01
vgremove vg01

Re: how to create volumegroup

Luk Vandenbussche — Fri, 30 Sep 2005 07:51:01 GMT

To add more disks

vgextend vg01 /dev/dsk/cxtydz