Is there an actual problem in my storage IO or is the data incorrect?
You need to divide io_stall_read_ms by num_of_reads, and io_stall_write_ms by num_of_writes. This will give you something more sensible as what you are seeing for read and write stalls and sum totals since your instance last stated up.

However, using this DMV in this manner can average out any spikes and hide patters, therefore you need to take samples from it every so often. Also I would recomend putting looking at your page life expectancy in conjunction with read latencies, go off Jonathan Kehayias's formula from SQL Skills.

Note that you need to look at PFE per NUMA node and if your application is OLAP you are unlikely to get a great PFE, your sequential scan rates being the more important metric here.