generally the storage naming convention called as Canonical Name, but there are differnt types and who assigns that name depend upon the ARRAY
if the array is not InterNational Committee for Information Technology Standards (T10).then for those arrays it is not mandatoy that... it will give a unique id in the form which ESX understands..
the different ways the esx labels the LUN is
ESX 3.X
- vmhba<Adapter>:<Target>:<LUN> or vmhba<Adapter>:<Target>:<LUN>:<Partition>
- vml.<VML> or vml.<VML>:<Partition>
- /dev/sd<Device Letter> or /dev/sd<Device Letter><Partition>
- <UUID>
There are 6 different ways ESX use to label storage.
ESX 4.X
- naa.<NAA> or naa.<NAA>:<Partition>
- eui.<EUI> or eui.<EUI>:<Partition>
- mpx.vmhba<Adapter>:C<Channel>:T<Target>:L<LUN> ormpx.vmhba<Adapter>:C<Channel>:T<Target>:L<LUN>:<Partition>
- vml.<VML> or vml.<VML>:<Partition>
- vmhba<Adapter>:C<Channel>:T<Target>:L<LUN>
- /dev/sd<Device Letter> or /dev/sd<Device Letter><Partition> (ESX only, not for ESXi)
- <UUID>
ESXi 5.x
- naa.<NAA>:<Partition> or eui.<EUI>:<Partition>
- mpx.vmhba<Adapter>:C<Channel>:T<Target>:L<LUN> or mpx.vmhba<Adapter>:C<Channel>:T<Target>:L<LUN>:<Partition>
- vml.<VML> or vml.<VML>:<Partition>
- vmhba<Adapter>:C<Channel>:T<Target>:L<LUN>
- <UUID>
NAA stands for Network Addressing Authority identifier. EUI stands for Extended Unique Identifier. The number is guaranteed to be unique to that LUN. The NAA or EUI identifier is the preferred method of identifying LUNs and the number is generated by the storage device. Since the NAA or EUI is unique to the LUN, if the LUN is presented the same way across all ESX hosts, the NAA or EUI identifier remains the same.
So normally the Array give the NAA id and esx just puts in he canonical name... and if the array didnt gave then esx will generate and puts in the canonical name...
i hope this clears the query