What action does the following command perform for a new AIX hdisk, hdisk1 ? chdev -I hdisk1 -a pv=yes

Making a disk available for use involves changing its state attribute (e.g., state=available), not assigning a physical volume identifier.

The pv=yes attribute does not change an existing PVID to the string 'Yes'; it stamps a new unique numeric identifier onto the disk if one is not already present.

Setting pv=yes instructs AIX to write a unique PVID into the reserved sector of hdisk1, formally registering it as a physical volume. This identifier is required by the LVM subsystem before the disk can be added to a volume group with commands like mkvg or extendvg. Without a PVID, the LVM subsystem will not recognize the disk as a valid physical volume candidate.

Clearing volume group descriptor locks requires using pv=clear or dedicated LVM recovery tools, not the pv=yes attribute.

Resetting the volume group descriptor area is a separate LVM recovery operation unrelated to stamping a PVID on a new disk.