How to perform tests for reading 64 KB files? My Website serves picture files with an average of 64 KB per file.

If you want to know how your environment performs on reading 64 KB files, you can use the following SQLIO options:

• "-LS" - Sets SQLIO to report latency measurements using the system timer.
• "-kR" - Sets SQLIO to perform reading tests.
• "-b64" - Specifies test block size to 64 KB, which represents the average file size on your Website.
• "-i64" - Specifies the run size of 64 I/O tests. This simulates the pattern of users requesting 64 different files in row.
• "-f64" - Specifies the stripe factor of 64 blocks. This simulates the pattern of users requesting consecutive files stored 64-file away from each other.
• "-t1" - Sets SQLIO to use 1 thread only. This simulates the pattern of a quiet Website that users comes one after another sequentially.
• "-s300" - Sets SQLIO to run for 300 seconds, or 5 minutes.

Below is a test result SQLIO with above options on a Dell computer hard disk with Windows 8:

C:\fyicenter\SQLIO>sqlio -LS -kR -b64 -i64 -f64 -t1 -s300

1 thread reading for 300 secs from file testfile.dat
        using 64KB IOs over 4096KB stripes with 64 IOs per run
size of file testfile.dat needs to be: 268435456 bytes
initialization done
CUMULATIVE DATA:
throughput metrics:
IOs/sec:   140.35
MBs/sec:     8.77
latency metrics:
Min_Latency(ms): 0
Avg_Latency(ms): 6
Max_Latency(ms): 1847
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+
%:  7  0  1  0  1 29 34 18  2  1  1  0  0  0  0  0  0  0  0  0  0  0  1  1  2

As you can see, this Dell computer is capable to read 140 files of 64 KB per second from the hard disk in a single thread without any buffering.

The average latency of reading a 64-KB block is about 6 milliseconds. In other words, your users should be able to fetch a file from your Website in 6 milliseconds if we ignore the impact of the Web server software.

The data file used in this test is of 268435456 bytes, or 256 MB, representing 64 x 64 (or 4096) 64-KB files.

⇒ Windows Resource Monitor - Disk Reading Speed

⇐ "sqlio -s300" - Get Stable Test Result

⇑ Tuning SQLIO for Your Environment

⇑⇑ SQLIO Disk I/O Benchmark Test Tutorials