Enhance alt_rootvg_op to preserve custom alternate rootvg name across wake/sleep operations

The alt_rootvg_op supports assigning a customer VG name to an alternate root VG, using -v. This is useful on systems that maintain multiple alternate root VGs for different purposes.

For example:

# lspv | grep MKSYSB 
hdisk0 00cc8df7ddd2f1e9 WEEKLY_MKSYSB  
hdisk13 00cc8df7536827de IMR_MKSYSB  

An administrator might need to wake one of these VGs:

# alt_rootvg_op -W -d hdisk13 
# INUCLIENTS=1 chroot /alt_inst /usr/bin/ksh -c "oslevel -s; emgr -lv3" 

However, when the alternate rootvg is put back to sleep:

# alt_rootvg_op -S 

Notice the VG was renamed to default:

# lspv 
hdisk13 00cc8df7536827de altinst_rootvg  

The administrator must then rename the volume group again.

# alt_rootvg_op -v IMR_MKSYSB -d hdisk13 

This creates some unnecessary risks:

• An administrator might inadvertently leave the VG named as altinst_rootvg

• Automation tools must be redesigned to determine and preserve the original VG name

• Loss of the descriptive name makes it difficult to determine which image is intended for which purpose.

• Only one altinst_rootvg is allowed. So if the VG is renamed to altinst_roovg upon sleep, any attempt to wake the second alternate rootvg would fail, and the administrator would have to independently validate the correct label for the current altinst_rootvg.

The alt_rootvg_op wake/sleep cycles should be non-destructive. While the name can remain altinst_rootvg while waking, we are requesting a change that would preserve any custom label set with alt_rootvg_op -v. Perhaps something as simple as storing the name during the wake, and restoring it upon sleep.

Thanks for your consideration!