What is the IO block size in KB option, "sqlio -b"?

The IO block size in KB option, "sqlio -b", controls the size of each data block used as a unit for each I/O test. The default value is "-b2", 2KB.

Example 1 - Run SQLIO with 4KB per data block:

C:\fyicenter\SQLIO>sqlio -b4

1 thread reading for 30 secs from file testfile.dat
        using 4KB IOs over 256KB stripes with 64 IOs per run
initialization done
CUMULATIVE DATA:
throughput metrics:
IOs/sec:  3729.90
MBs/sec:    14.56

Example 2 - Run SQLIO with 8KB per data block:

C:\fyicenter\SQLIO>sqlio -b8

1 thread reading for 30 secs from file testfile.dat
        using 8KB IOs over 512KB stripes with 64 IOs per run
initialization done
CUMULATIVE DATA:
throughput metrics:
IOs/sec:   407.44
MBs/sec:     3.18

Example 3 - Run SQLIO with 16KB per data block:

C:\fyicenter\SQLIO>sqlio -b16 -LS

1 thread reading for 30 secs from file testfile.dat
        using 16KB IOs over 1024KB stripes with 64 IOs per run
initialization done
CUMULATIVE DATA:
throughput metrics:
IOs/sec:   156.40
MBs/sec:     2.44

As you can see, reading a larger block takes longer time as we expected. The throughput goes down means that each block is taking longer to finish.

⇒ "sqlio -f" - Stripe Size in Blocks

⇐ "sqlio -s" - Number of Seconds to Run

⇑ Getting Started with Microsoft SQLIO

⇑⇑ SQLIO Disk I/O Benchmark Test Tutorials