topic Re: Cannot Create Volume Group with SAM in Operating System - HP-UX

Cannot Create Volume Group with SAM

yyghp — Tue, 19 Oct 2004 17:16:00 GMT

I have two servers(HostA and HostB) connected to EVA5000, I presented some LUNs(200GB) of EVA5000 to these two servers, and I successfully created a VG on one 200G with SAM 3 weeks ago. Now, when I tried to create more VGs on those 200GB LUNs, but failed this time :(

When I used SAM, I got the following error message:
"No device files for the selected device were found in /dev"
And here's the detail I got it from SAM log:
----- Tue Oct 19 17:06:37 2004: Adding the disk at hardware path 255/255/0/0.1
with LVM.
* Creating the device files for the disk at 255/255/0/0.1, using the sdisk
driver.
* Creating device files.
* Creating the device file /dev/rdsk/disk_query.
* Creating a specific device file.
* Using libIO calls to make device file (name,hw_path,mode,options):
(/dev/rdsk/disk_query, 255/255/0/0.1, 0, )
* Creating the device file /dev/rdsk/disk_query.
* Creating a specific device file.
* Creating the device files for the disk at 255/255/0/0.1, using the sdisk
driver.
* Creating device files.
* Creating the device file /dev/rdsk/disk_query.
* Creating a specific device file.
* Using libIO calls to make device file (name,hw_path,mode,options):
(/dev/rdsk/disk_query, 255/255/0/0.1, 0, )
* Successfully created /dev/rdsk/disk_query.
* Creating the device file /dev/dsk/disk_query.
* Creating a specific device file.
* Using libIO calls to make device file (name,hw_path,mode,options):
(/dev/dsk/disk_query, 255/255/0/0.1, 1, )
* Successfully created /dev/dsk/disk_query.
* Creating the device file /dev/dsk/disk_query.
* Creating a specific device file.
* Using libIO calls to make device file (name,hw_path,mode,options):
(/dev/dsk/disk_query, 255/255/0/0.1, 0, )
* Successfully created /dev/dsk/disk_query.
* Creating volume group vg02.
* Performing task "Installing device files for a specific hardware path.":
Installing device files for hardware path 255/255/0/0.1 .
* Executing the following command:
/sbin/insf -eH 255/255/0/0.1
* Command completed with exit status 0.
ERROR No device files for the selected device were found in /dev.

But I am sure I can see all LUNs from server side:

# ioscan -fnC disk
Class I H/W Path Driver S/W State H/W Type Description
==========================================================================
disk 0 0/0/3/0.0.0.0 sdisk CLAIMED DEVICE TEAC DV-28E-C
/dev/dsk/c0t0d0 /dev/rdsk/c0t0d0
disk 1 0/1/1/0.0.0 sdisk CLAIMED DEVICE HP 73.4GST373453LC
/dev/dsk/c2t0d0 /dev/rdsk/c2t0d0
disk 2 0/1/1/0.1.0 sdisk CLAIMED DEVICE HP 73.4GST373453LC
/dev/dsk/c2t1d0 /dev/rdsk/c2t1d0
disk 3 255/255/0/0.0 sdisk CLAIMED DEVICE HSV110 (C)COMPAQ
/dev/dsk/c12t0d0 /dev/rdsk/c12t0d0
disk 5 255/255/0/0.1 sdisk CLAIMED DEVICE HSV110 (C)COMPAQ
/dev/dsk/c12t0d1 /dev/rdsk/c12t0d1
disk 6 255/255/2/0.0 sdisk CLAIMED DEVICE HSV110 (C)COMPAQ
/dev/dsk/c18t0d0 /dev/rdsk/c18t0d0

( NOTE: now, I already had VG on "/dev/dsk/c12t0d0", but can't create VG on "/dev/dsk/c12t0d1" or '/dev/dsk/c18t0d0" )

And I don't have problem to receate the device file with "insf" and check diskinfo:

# insf -eH 255/255/0/0.1
insf: Installing special files for sdisk instance 5 address 255/255/0/0.1

# diskinfo /dev/rdsk/c12t0d1
SCSI describe of /dev/rdsk/c12t0d1:
vendor: COMPAQ
product id: HSV110 (C)COMPAQ
type: direct access
size: 209715200 Kbytes
bytes per sector: 512
# diskinfo /dev/rdsk/c18t0d0
SCSI describe of /dev/rdsk/c18t0d0:
vendor: COMPAQ
product id: HSV110 (C)COMPAQ
type: direct access
size: 104857600 Kbytes
bytes per sector: 512

And I've applied the latest SAM patch to the system, I don't think SAM's bug for EVA makes the problem here.

Then, I tried to use command line to create VG instead of using SAM:

# pvcreate /dev/rdsk/c12t0d1
Physical volume "/dev/rdsk/c12t0d1" has been successfully created.
# mkdir /dev/vg02
# mknod /dev/vg02/group c 64 0x020000
# vgcreate /dev/vg02 /dev/dsk/c12t0d1
Increased the number of physical extents per physical volume to 51199.
vgcreate: Volume group "/dev/vg02" could not be created:
VGRA for the disk is too big for the specified parameters. Increase the
extent size or decrease max_PVs/max_LVs and try again.

# vgcreate -e 65533 -l 4 -p 4 -s 8 /dev/vg02 /dev/dsk/c12t0d1
Volume group "/dev/vg02" has been successfully created.
Volume Group configuration for /dev/vg02 has been saved in /etc/lvmconf/vg02.conf

So, it seems we cannot use SAM for this case...
Any comment on this ?
Thanks !

Re: Cannot Create Volume Group with SAM

Sridhar Bhaskarla — Tue, 19 Oct 2004 17:35:16 GMT

Hi,

I cannot comment on why SAM failed as I never use SAM to work on LVM components.

For the initial command line failure, if you don't specify a PE size, then it will be defaulted to 4MB. VGRA is written as a table in the first Physical Extent of the PV. If table resulted by the combination of your max PE and PE size doesn't fit in 4MB, then you see this error. So, you will need to either increase the PE size or decrease the max PEs to accommodate the VGRA in that one extent.

-Sri

Re: Cannot Create Volume Group with SAM

Steven E. Protter — Tue, 19 Oct 2004 19:39:28 GMT

SAM did not fail. Patching will not help.

An underlying command in, vgcreate failed because the parameters sent to it were not correct.

Your vgcreate command contained customizations required to successfully create the volume group.

SAM wasn't programmed to cover every eventuality, though I think if you looked at the options for vgcreate in SAM you might find a way to get it to issue the vgcreate command that you eventually issued.

A lesson can be learned here. LVM work is best done on the command line. The main reason is if you ever have to go into lv maintenance mode or single user mode sam wont be there to help. You'll need to know the commands yourself.

To quote Bill Hassel, Real sysadmins's don't use GUI's. Though the first time I heard the remark, I got upset, I later learned the truth.

I try and do everything I can not from the command line. About the only thing I do with SAM is test it when building a system so its working for my backup. That and set up EMS which I've never bothered to learn how to do any other way than SAM.

Its a great investment of your time to learn how to do LVM from the commmand line. This is not the first time you are going to find thats the best way to go. I'd recommend doing before you have to learn it in a crisis.

Almost every sysadmin has had a failure or mistake and been forced to do disk work in single user or lv maintenance mode.

Good Luck.

SEP

Re: Cannot Create Volume Group with SAM

yyghp — Wed, 20 Oct 2004 12:10:43 GMT

Hi Steven,

Thanks for your comments about command line. Yes, I know a sysadm should use command line instead of GUI, I get used to do everything via different way.

Now, the problem is that SAM has the option to let me input those parameters, like Max PE, Max LE, and PE size, but I still had the same problem when I used those parameters ( exactly the same as those I used in command line ), I got the same error.
That's why I raise this question.
Thanks !

Re: Cannot Create Volume Group with SAM

Sridhar Bhaskarla — Wed, 20 Oct 2004 13:31:57 GMT

Hi,

Run '/usr/sam/bin/samlog_viewer' and see what commands SAM ran. Or you can 'view' /var/sam/log/samlog to search for yourself.
You may get clues there.

-Sri