old_rootvg is an alternate disk image - you cannot varyon it, you can wake it up with

Code:

alt_disk_install -W hdiskx

(alt_disk_install -S hdiskx puts it asleep again) or you can boot from it by changing the boot list of your server to this disk.

Generally when a VG appears in the output of lsvg command, than its imported, if the same VG appears in output of lsvg -o than its imported and varied on.

Hope this helps
regards
zxmaus