Remove the empty query, or provide some sort of value to query by, from the ZAPI call. Also, you'll want to remove the "desired-attributes" section as well...leaving it out, or with no "volume-attributes" section, will cause it to return all data (assumign that's what you want). With what you have in the ZAPI I believe it will only return the volume name and UUID.
Using simply "<volume-get-iter />" will return all volumes and all attributes.
<netapp xmlns="http://www.netapp.com/filer/admin" version="1.30">
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