Hi Dnyadev,
Number of sapdata files depends on the ease of manageability.
Standard recommendation goes with 4 sapdata files.
To address the performance objective, you can have multiple disks configured in RAID and stripping created across the disks. You need to ensure that number of I/Os are good while designing the layout. You may speak with your hardware partner on how to achieve this.
Sample example for ECC
DB size = 18 TB
I shall go with 6 sapdata files each of 3 TB each.
Disks type used in the storage will be of 450GB / 600GB and shall have RAID 5 to have good read/write operations.
Hope this helps.
Regards,
Deepak Kori