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Activate VG in shared mode

Occasional Visitor

Activate VG in shared mode

Hi there,

According to Oracle manual, either CRS or Clusterware is required to activate the VG storing VOTE and OCR raw devices by the following command:

vgchange -a s vgname

But it gets this error message whenever issued such command:

" ... the volume group conflicts with configured mode."

I've tried to re-install everything including the OS (11.23 OE) but still ...

Please help me on this.

Devender Khatana
Honored Contributor

Re: Activate VG in shared mode


The vg sharing is applicable only within service guard nodes that too on cluster marked VGs. Capture from man vgchange
s Activate each specified volume
group and all associated physical
and logical volume for shared
read-write access. The volume
group must be marked as part of a
high availability cluster and

Hewlett-Packard Company - 2 - HP-UX Release 11i: November 2000

vgchange(1M) vgchange(1M)

marked sharable; otherwise, the
volume group is not activated.

If any of the logical volumes in
the volume group are mirrored, and
if there are more than two systems
in the high availability cluster,
this volume group will not be
activated because HP MirrorDisk/UX
software is only supported in a
clustered environment with a
maximum of two nodes configured.

Also you should have only two nodes in the cluster to achive this.

Impossible itself mentions "I m possible"
Abhijit P.
Valued Contributor

Re: Activate VG in shared mode


If this is Cluster Setup i.e. Machine service guard you can try the following which activates the VG in a shared mode

1. Execute the command:
vgchange -a n /dev/vgxx
to deactivate the volume group.

2. Execute the command:
vgchange -c n /dev/vgxx
to detach from cluster.

Now it will successfully activate, and you can see all the
logical volumes and mount them.

3. Execute:
vgchange -c y /dev/vgxx
to return the volume group to the cluster when you are done.

Sivakumar TS
Honored Contributor

Re: Activate VG in shared mode


Please run,

#vgchange -c y -S y /dev/vgname

This will enable the VG cluster and mark as sharable

Then you can proceed with

#vgchange -a s vgname

With Regards,

Nothing is Impossible !
Honored Contributor

Re: Activate VG in shared mode


# vgdisplay vgname|grep "Vg Status"

normal mode -> available
sguard mode -> available, exclusive
share mode -> available

# vgchange -a y -s /dev/vgname

vgchange: Activation mode requested for the volume group "/dev/vgname" conflicts with configured mode.

If mode "exclusive":

# vgchange -a n vgname
# vgchange -c n vgname
# vgchange -a y -s vgname

Esteemed Contributor

Re: Activate VG in shared mode

SG by itself is not enough for shared VGs.
Cluster VGs "-c" are NOT shared -- they cannot be open at same time on different nodes.

With SG + RAC + sharedVGS, you need the SGeRAC extension that allows actual SHARED VGs -- i.e., activated r/w two nodes at same time.

If you use CRS, then you don't need SG or shared VGs.
You can use 10g + raw devices + ASM.
However, you need to be able to dedicate 2 raw devices; one for OCR and one for Voting disk that can be very small. The Ideal is to be able to create 2 small LUNs on an array. For a MSA1000, you can create 100MB and 300MB LUNs for this use. For an EVA, the smallest you can create is 1GB, thus 2GB for OCR+Vote, where 400MB would suffice.

The advantage of shared VGs is that you can create 2 small raw LVOLs for the OCR and the Vote disk and carve up the VG into LVOLs of suitable size rather than having to size LUNs in the Array correctly.

"The lyf so short, the craft so long to lerne." - Chaucer
Kent Ostby
Honored Contributor

Re: Activate VG in shared mode

And note that the SGeRAC that allows shared VGs does not allow shared FILESYSTEMS, but rather shared RAW PARTITIONS.

Shared filesystems is probably down the pipe somewhere, but not currently.

"Well, actually, she is a rocket scientist" -- Steve Martin in "Roxanne"