Explanation/Reference:
Second write workload IOPS = 2 GB/s divided by 128 kB = 2 x 1,073,741,824 / (128 x 1,024) = 16384 IOPs.
Total IOPS required would be 150,000, from the first workload, plus 16384, totaling 166384.
A 2 X-Brick cluster provides 300K Read/write IOPS so it would be adequate.
Storage capacity and performance scale linearly, such that two X-Bricks supply twice the IOPS, four X- Bricks supply four times the IOPS, six X-Bricks supply six times the IOPS and eight X-Bricks supply eight times the IOPS of the single X-Brick configuration.
Note: Choose an EMC XtremIO system and scale out linearly by adding more XtremIO X-Bricks.

References: https://store.emc.com/en-us/Product-Family/EMC-XtremIO-Products/EMC-XtremIO-All-Flash- Scale-Out-Array/p/EMC-XtremIO-Flash-Scale-Out