In linux I have an app that constantly reads/writes many small files (e.g close to zero bytes), millions of them to a point where disk innodes are close to 100%. 
And 1000-4000 files read/written each minute.
I was wondering what is the best HDD setup to improve performance when these files are read/write by more instances at once ?

- 4 SSD in raid 0 ?
- 2/3 SSD in raid 0 ?
- 4 HDD raid zero ? (because I think SSDs drop in performance after so many permanent writes)
- raid 0 included in Asus motherboard ?
- dedicated raid car ?