How to perform tests for writing 1 MB files? I want to see the impact of file size on writing files.

If you want to see the impact of file size on writing files, try to increase the block size from 64 KB to 1024 KB (1 MB), and keep the other options unchanged:

C:\fyicenter\SQLIO>sqlio -LS -kW -b1024 -i64 -f64 -t1 -s300

1 thread writing for 300 secs to file testfile.dat
        using 1024KB IOs over 65536KB stripes with 64 IOs per run
        affinity on cpu number 0
size of file testfile.dat needs to be: 4294967296 bytes
initialization done
CUMULATIVE DATA:
throughput metrics:
IOs/sec:    55.84
MBs/sec:    55.84
latency metrics:
Min_Latency(ms): 2
Avg_Latency(ms): 17
Max_Latency(ms): 318
histogram:
ms: 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24+
%:  0  0  2 24  7  1  0  0  0  0  0  1  2  9  7 12  9  5  2  1  1  1  1  1 15

Comparing to the previous test of writing 64-KB blocks, the throughput of writing 1024-KB blocks increased from 30.45 MBs/sec to 55.84 MBs/sec. This tells us that this Windows environment is more efficient on writing larger files, because of operating system caching mechanism.

Comparing to the reading test of the same block size of 1024 KB, writing speed, 55.84 MBs/sec, is still a little bit faster than the reading speed, 53.48 MBs/sec. Again, this is not a hardware issue. This is a result of operating system caching mechanism.

⇒ Western Digital - WD5000LPLX-08ZNT - Maximum Reading Speed

⇐ "sqlio -kR -b1024" - Reading 1-MB Block Test

⇑ Tuning SQLIO for Your Environment

⇑⇑ SQLIO Disk I/O Benchmark Test Tutorials