[Linux-cluster] iscsi and clusterd volume group

[Robert Peterson]

nirmal tom wrote:
> hi,
> as per the usage guide , i activated the c or clustered bit for the 
> volume group, rac.Now it is shown to my kernel or system.So, the iscsi 
> target fails and whatever command i gave with respect to lvm it simly 
> reponds skipping as u see below
> 
> [root at server ~]# vgchange -a y rac
>  Skipping clustered volume group rac
> [root at server ~]# vgchange -c n rac
>  Skipping clustered volume group rac
> [root at server ~]# vgremove rac
>  Skipping clustered volume group rac
> [root at server ~]# vgchange --clustered n rac
>  Skipping clustered volume group rac
> ered volume group rac
> [root at server ~]# vgchange --available e y rac
>  Volume group "y" not found
>  Skipping clustered volume group rac
> 
> how to set the clustered bit to turn off? or to make it avialabel as usual
> 
> thanks for any response
> 
> regards,
> Nirmal Tom.

Hi Nirmal,

I think what happened here is that maybe you have 
locking_type = 2 but clvmd isn't running.  Therefore,
lvm can't do the clustered locking necessary to "see" the
volume group, and it has to "see" the volume group before
it can change its attributes.

Your choices are to (1) activate the clustered locking
mechanism and leave the volume group clustered, or 
(2) change the locking_type = 1 in your 
/etc/lvm/lvm.conf file, at least temporarily, so you can
change the clustered bit off.

To get the clustered volume to be active, make sure
locking_type = 2 (for RHEL4 and similar) or locking_type = 3
(for RHEL5 and similar) in /etc/lvm/lvm.conf, then you need
to run the clustered LVM manager: service clvmd start.
The clvmd service can only run properly, however, if the rest
of the cluster infrastructure is running.

If you're sharing the volume group between systems, you
want to keep the clustered bit on.  If not, you can turn it off.

After clvmd is started, or locking_type changed back to 1,
you should be able to do what you want.  For example:

vgscan
vgchange -aln
vgchange -cn rac 

Regards,

Bob Peterson
Red Hat Cluster Suite