Hi Srimurgan,
In cDOT, I was able to get information about instances.
[rle@pale]{/u/rle} ontapi rtp-cse-cl01 myPass perf-object-instance-list-info-iter objectname nfsv3
<results status="passed">
        <attributes-list>
                <instance-info>
                        <name>PrivateCloud</name>
                        <uuid>7</uuid>
                </instance-info>
                <instance-info>
                        <name>dtmgmt</name>
                        <uuid>15</uuid>
                </instance-info>
                <instance-info>
                        <name>vs-cse-01</name>
                        <uuid>4</uuid>
                </instance-info>
                <instance-info>
                        <name>vs-orng-01</name>
                        <uuid>6</uuid>
                </instance-info>
                <instance-info>
                        <name>vs1</name>
                        <uuid>3</uuid>
                </instance-info>
                <instance-info>
                        <name>wfatest</name>
                        <uuid>13</uuid>
                </instance-info>
        </attributes-list>
        <num-records>6</num-records>
</results>
It looks like each instance is a vserver.  There are other counter objects like nfsv3:node, nfsv3_cpu, etc.  My blog might be helpful.
Regards,
   - Rick -