HP-UX ServiceGuard Secondary Node LVM Awareness

[coke]

Forum Post: HP-UX ServiceGuard Secondary Node LVM Awareness Problem Statement:

After expanding storage and extending LVM on ServiceGuard primary node, how to ensure secondary node recognizes the changes for proper failover?

Scenario:

• Storage admin expanded LUNs from 100GB to 150GB at SAN level
• diskinfo shows correct 240GB size on primary nodes
• Primary node: Successfully extended using vgmodify, lvextend, fsadm
• Filesystems now 240GB and Oracle running normally

Challenge:

Secondary node has inactive/shared VG - cannot verify LV sizes or filesystem capacity without activating VG. Standard LVM commands (vgdisplay, lvdisplay) fail on inactive VGs.

Current Status:

• Primary node: VG active, all filesystems extended to 240GB
• Secondary node: VG inactive, cannot verify LV configuration
• ServiceGuard package running normally on primary

Questions:

1. How to verify secondary node sees extended LV sizes without activating VG?
2. Does LVM metadata sync automatically to shared storage, or additional steps needed?

Environment Details:

• HP-UX 11.31, ServiceGuard A.11.20
• LVM with shared storage (3PAR)
• VxFS filesystems
• Oracle databases

Looking for ServiceGuard/LVM experts who have handled similar storage expansions in clustered environments.

[mbarnwal]

While the VG is active and filesystems are mounted on primary node, you can still activate the VG on other node in (only) read-only mode.

vgchange -a r <vg name>

Then you can mount the filesystems and check the size. Again, you would be able to mount the filesystems in read-only mode only.

mount -o ro /dev/<vg name>/<lv name> /mnt

Once done with verification, do not forget to unmount the filesystem and deactivate the vg

umount /mnt

vgchange -a n <vg name>

[coke]

thank you. this tells me we can safely activ ate a VG in ro mode, mount the mounts in ro mode

safely means - it wont affect the actual live mount in pri node. I do not know yet if i can try that yet - but thank you.

However I still wonder what is the approach for a mount which is a package - in  a HP Service guard

There might be scenarios where you need to either add a disk or expand a disk to expand FS/mount point size 

you do all the work in primary node to make LVM aware of increased size - but what do we need to do in secondary node

Thank you again,.

[mbarnwal]

If there are any changes to VG on primary node, like addition/removal of PV, you should redistribute the VG to update /etc/lvmtab on other cluster nodes using vgexport/vgimport method.

Refer "Distributing the Volume Group" in SG guide 

https://support.hpe.com/hpesc/public/docDisplay?docId=a00062147en_us&docLocale=en_US