What is the role and concept of SVM
Its replacing a concept called vfiler on 7-mode where you could have multiple instances of the filer. i'ts not running another OS. just a thread with required client processing services and it's own routing domain
What is the concept of virtual WWN#
Replacing a File in 7-mode where the WWN were software assigned instead of using the physical HBA one. this help when you replacing the node or moving the LIF's around so you don't need to re-configure zooning (if they are WWN based).
What is the difference between Aggregate and storage pools.
Aggr is an actual storage object based on collection of raid-groups (that based on Disks), and can host Volumes on. Storage pool is a concept to share a spare SSD Flash Pool drives between nodes in the HA to save cost on SSD Spares (https://library.netapp.com/ecmdocs/ECMP12407870/html/GUID-4816CED0-67B9-4D08-90C8-B80930080246.html)
What’s the benefit b/w normal aggregate and tier aggregate?
Tier allow you to move data between different types of back end disks according to a policy. a normal AGGR (That is not flash pool) will just spread the load on all the disks randomly.