Infrastructure Software

We are migrating our DW to new servers but before we install Oracle we want
to check IOPS of new servers. As Oracle and other technical expert suggests we
are planning to create the DB with 32K block size with DBMRC=32 so total IO
size of 1 M but the test I performed does not support that theory. Please advise
where I am wrong OR what is the best way to check the throughput:
Here are my results:
1. Created a 2 GB file deleteme
2. For 32*32 results are: (block size=32, db_block_multi_read-count=32)
time dd if=deleteme of=deleteme2 bs=1048576 (32*32)
2048+0 records in
2048+0 records out
real 0m42.94s
user 0m0.00s
sys 0m1.22s
Result: 47.69 IOPS 1MB each.
2. For 32*8 results are: (block size=32, db_block_multi_read-count=8)
time dd if=deleteme of=deleteme2 bs=262144 (32*8)
8192+0 records in
8192+0 records out
real 0m28.12s
user 0m0.02s
sys 0m3.69s
Result: 291.32 IOPS 256K each.
Based upon above is it better to have IO size for the DB as 256K? Please advice.

Thanks in advance.