Issue with LVM Disk and Help in Creating Disk

[Jon Le]

Hello everyone. Here are some details beforehand.

ioscan:
I have a HP-UX 9000, class RP5430.

the following scan is for a DS2100 external disk enclosure that has 3 harddrive in place.

0/3/0/0.0.0
sdisk claimed device seagate ST318404LC
/dev/dsk/c7t0d0
/dev/rdsk/c7t0d0

0/3/0/0.2.0
sdisk claimed device HP 18.2GST318406LC
/dev/dsk/c7t2d0
/dev/rdsk/c7t2d0

0/3/0/0.4.0
sdisk claimed device HP 18.2GST318406LC
/dev/dsk/c7t4d0
/dev/rdsk/c7t4d0

I had a disk go bad or a configuration error but I was using c7t0d0. However that disk got replaced and I want to use c7t0d0.

When I go into SAM in Disk Devices, it shows all 3 "unused".

Here is what I am trying to do. Begin to use all 3 disk. Each of the disk is 18.2 gig so I would like to have a volume group of 54.6 gig and possibly add more at a later date.

Here is the problem that I am running into:

when I do the following, i get the this error:

# pvdisplay /dev/dsk/c7t0d0
pvdisplay: Warning: couldn't query physical volume "/dev/dsk/c7t0d0": This specified path does not correspond to physical volume attached to this volume group
pvdisplay: warning: couldn't query all of the physical volumes.
pvdisplay; couldn't retrieve the names of the physical volumes belonging to volume group "/dev/test"
pvdisplay: cannot display physical volume "/dev/dsk/c7t0d0"

#vgdisplay /dev/test
vgdisplay: volume group not activated
vgdisplay: cannot display volume group "/dev/test"

#lvdisplay /dev/test/lvol1
lvdisplay: couldn't query logical volume "/dev/test/lvol1"
volume group not activated.

How do I go about resolving this error??

Also if you can provide me with a step by step instruction on how to start using the 3 disk. I know the steps involved but would like to confirm it with you guys. Thank you for your help in this matter.

[James R. Ferguson]

Hi Jon:

> vgdisplay /dev/test
> vgdisplay: volume group not activated

This means that the volume group is not active, so do:

# vgchange -a y /dev/test

Regards!

...JRF...

[Jon Le]

tried to activate it however here is what i am getting:

# vgchange -a y /dev/test

vgchange: warning: couldn't attach to the volume group physical volume "/dev/dsk/c7t0d0":
Cross device link
vgchange: warning: couldn't query physical volume "/dev/dsk/c7t0d0":
the specified path does not correspond to physical volume attached to this volume group
vgchange: warning: couldn't query all of the physical volume.
vgchange: couldn't activate volume group "/dev/test"
Quorum not present, or some physical volume(s) are missing.

Thank you for the quick response.

[melvyn burnard · Accepted solution]

well if your disk has been replaced, you need to recreate the LVM headers on it.
Firstly though, do a strings /etc/lvmatb and verify what disks are in vg named test

If all three disks are listed, you can use vgcfgrestore to recreate the headers from the backupfile
man vgcfgrestore.

[Jon Le]

when I do a strings /etc/lvmtab

i get the following:

# strings /etc/lvmtab

/dev/vg01
/dev/dsk/c1t0d0
/dev/dsk/c2t0d0
/dev/dsk/c2t2d0
/dev/vg00
/dev/dsk/c1t2d0
/dev/test
/dev/dsk/c7t0d0

This is what is in my fstab file:

/dev/vg00/lvol3 / vxfs delaylog 0 1
/dev/vg00/lvol1 /stand hfs delaylog 0 1
/dev/vg00/lvol4 /tmp vxfs delaylog 0 2
/dev/vg00/lvol5 /home vxfs delaylog 0 2
/dev/vg00/lvol6 /opt vxfs delaylog 0 2
/dev/vg00/lvol7 /usr vxfs delaylog 0 2
/dev/vg00/lvol8 /var vxfs delaylog 0 2

/dev/vg01/data /data vxfs rw,suid,largefiles,delaylog,datainlog 0 2

/dev/test/lvol1 /test vxfs rw,suid,largefiles,delaylog,datainlog 0 2

[Torsten.]

The disk is still empty, but you have a valid VG backup for this disk.

# vgcfgrestore -n vgtest /dev/rdsk/c7t0d0

will restore the config.

# vgchange -a y vgtest

will activate the VG.

# vgdisplay -v vgtest

Now you need to do a "newfs" to the LVOLs (if there are any) to make them useable.

[Jon Le]

how do I start from scratch. Delete everything and begin from nothing.

[Torsten.]

You need to vgexport the vgtest in order to remove it from /etc/lvmtab.

man vgexport

[Jon Le]

thank you, i would run the following:

# vgexport -v -f backup /dev/test


after I do that, I can start with

1. creating a PV (pvcreate)
2. vgcreate
3. lvcreate

[Tim Nelson]

Here is what I would do after a bad disk replacement ( you can vgexport as mentioned because the data is gone any way) but this is good practice.

Remove old drive, insert new one.
ioscan
ioscan -kfnC disk ( look for your c7t0d0 disk as claimed)

vgcfgrestore -l -n /dev/vgtest ( this lists what devices the vgtest thinks it has)
vgcfgrestore -n /dev/vgtest /dev/rdsk/c7t0d0
vgchange -a y /dev/vgtest
vgdisplay -v /dev/vgtest

( In this case because you only had one drive and it is replaced, data is gone so.. )

newfs /dev/vgtest/rlvol1
mount /test-filesystem

or just start over

vgexport /dev/vgtest
pvcreate /dev/rdsk/c7t0d0
mkdir /dev/vgtest
mknod /dev/vgtest/group c 64 0x0Y0000 (pick a unique minor number for Y )
vgcreate /dev/vgtest /dev/dsk/c7t0d0
lvcreate -L SIZE_MB -n NAME /dev/vgtest
newfs /dev/vgtest/rNAME
edit /etc/fstab
mount /new_test_filesstem