I am having trouble collecting list of volumes on a C-dot system. I tried volume-get-iter and it returns as passed with 0 records. Also the same problem with perf-object-instance-list-info-itr. Below is the output I am seeing.
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.