Can't create LV in "distributed volume group"?

[Michael Simone]

I'm running a 2-node MC/SG setup with my SG volumes on an XP256. I'm trying to create a new logical volume in one of my volume groups (which has plenty of space). When I go into SAM and try to select vg02 to Create an LVOL in, I get this error:

****You have specified a volume group which is currently distributed. Distributed volume groups cannot be modified until they have first been made distributed.
To undistribute a distributed volume group, go to the "Volume Groups" subarea, select the distributed volume group from the list given -- there, and select "Undistribute" from the "Actions" menu.*******

I first assumed "Distributed" referred to Serviceguard, but now I'm not so sure. And I'm leery of following these instructions to "undistribute" the volume group--I'm doing this all online, and I can't have that volume group become unavailable to the active node.

I have found NO documentation anywhere on HP's site discussing "distributed volume groups", much less what "undistributing" one does to it.

Could someone please explain this? Thanks.

[Sridhar Bhaskarla]

Michael,

As far as my knowledge goes, distribution is associated with the logical volumes not the volume groups. However, check the following.

1. If you are using PVGs make sure your /etc/lvmpvg files are intact.
2. Make sure the volume group is not activated on the other node. You can do a vgchange -a n vg02 on the system that is not running the package.
3. Do a vgdisplay vg02 and check if you see anything suspecious.
4. Try command line option and see what the error you are getting.

#lvcreate -L some_size -n lvol? vg02

-Sri

[Sanjay_6]

Hi Michael,

Try this on the node where this VG/LV is active.

# umount /dev/vg_name/lvname
# lvextend -L new_size_of_lv_in_MB /dev/vg_name/lv_name
# extendfs -F vxfs /dev/vg_name/rlvname
# mount -F vxfs /dev/vg_name/lvname /mount_point

Hope this helps.

Regds

[Michael Simone]

Maybe I didn't make clear that whatever the solution here is, I can't unmount this filesystem because it's in a Serviceguard environment.

Thanks for the try anyway.

[A. Clay Stephenson]

Sorry this dog won't hunt. You can't modify a VG on a running package like this. You are going to have to halt the package first.

[Sanjay_6]

Hi Michael,

you cannot modify the size of a filesystem until you have onlineJFS. Do you have online JFS loaded on your system. If so you can use the fsadm command to modify the filesystem size online. If you don't have onlineJFs you have to unmount the filesystem to increase the lv size.

Hope this helps.

Regds

[Sanjay_6]

Hi Clay,

You can modify the Vg and the Lv even if they are activated on the SG node. the only factor you have to look for is that they should not be in use.

Regds

[Sridhar Bhaskarla]

I don't know what's with SAM but you can definitely add a logical volume to the volume group that has been activated through ServiceGuard. You do not need to halt package. Only thing is to make sure we re-import the volume group on the other node. or manually create device files for the new logical volume that has been added. Also make sure that the control file has been updated with the new logical volume on both the nodes.

Have you tried through command line yet?.

-Sri

[Michael Simone]

Sri,

I hoped you'd say that. I haven't tried command line yet, only because I wanted someone to assure me that if I try it, it's not going to automatically deactivate that VG or unmount the filesystems. I was hoping to just do an lvcreate and newfs--is it safe? I don't care if it fails, as long as it doesn't bring my package down with it.

Thanks for the help!

[G. Vrijhoeven]

Hi,

Lots of replies and i like to add one:

Check of the package is running if so halt it, or buy online jfs. if not use vgchange -a e to exclusifly activate the volume group on your host. use vgchage -c n to deactivate the cluster bit and vgchange -a y to activate it again. Now you can use all the normal commands. at the end reverse the process!

Gideon

[Sridhar Bhaskarla · Accepted solution]

Michael,

The volume group is already active on the system and you don't have to touch it at all. Simply do an lvcreate and then newfs.

#lvcreate -n lvol? -L size vg02
#newfs -F vxfs /dev/vg02/rlvol?
#mount /dev/vg02/lvol? /?

Now make sure you update the package control file to include this logical volume and the mount point. Make change/sync to the other node also.

You need to reimport the volume group on the other node too because these new logical volume device files will not be present on it.

-Sri