If using a nas, it is better to write whole complete files to it. Not records or blocks one at a time.
Advanced storage:
If you are using a complete disk for large video file storage (BVR) continuous recording, I recommend formatting the disk, with a windows cluster size of 1024K (1 Megabyte). This is a increase from the 4K default. This will reduce the physical number of disk write, decrease the disk fragmentation, speed up access.
THanks
I have put a 2TB seagate skyhawk HDD in the NVR PC and set BI to write NEW clips to that
I can also format it like you said