https://h20195.www2.hpe.com/v2/getdocum ... 0000244enwURE
Biggest reason ever to run RAID6. Full 4TB SSDs, R5 7+1. Disk failure (ignoring spare and that stuff) will need to read n* disk size (where n is the R5 n+1). So that will read 7*4TB = 28TB of data. With one URE every ~1 PB of data you have a ~2.8% of URE (or about 1 in every 40).
This is generic for the entire storage industry and the reason why (as far as I know) no storage vendors recommend single-parity RAID on any enterprise storage systems anymore.
If you chose performance (yes R6 will have ~65% more backend IO for write compared to R5, read is still just a single IO for both) over data security, then I hope you've cleared that with the guys in the suits and with the higher pay grade. Because they will not be happy the day you hit that URE with RAID5, and it is only a matter of time.
If capacity is important, R6 14+2 is an option.