When troubleshooting
performance problems, you need to know the throughput rates of any
file system that SAS uses. The Sasiotest utility performs the following
actions:
-
measures the I/O behavior of the
system under defined loads
-
opens files and reads and writes
data, similar to SAS I/O
-
creates and writes files to the
file system that is being tested, and reads them to test Write and
Read performance
-
writes an output file that captures
elapsed real time and I/O rate, expressed as megabytes per second
-
-
can run several I/O tests concurrently
to overload the file system and determine its performance
The following information
relates to how the Sasiotest utility operates on Windows:
-
runs on 32-bit and 64-bit Windows
systems
-
is delivered with SAS and is installed in the SASHOME
directory at
\SASHome\SASFoundation\9.4\sasiotest.exe
-
is a stand-alone program, and can be launched from a
command prompt window
-
uses the Windows APIs Writefile(),
Readfile(), and Closefile()
-
supports the Readfilescatter()
and Writefilescatter() APIs for Scatter-Gather
I/O testing outside the file
cache
-
can be copied and used as a stand-alone
executable on any system with or without SAS
-
can be copied and used on a machine
that has previous SAS releases
For
information about how SAS performs
I/O and the minimum
I/O recommendations
for SAS file systems, see the SAS papers available at
http://support.sas.com/kb/42/197.html. The papers outline recommended
I/O metrics for file
systems that support SAS deployments, and they identify guidelines
that can help tune
I/O characteristics for optimal SAS performance.
If you are testing your file system throughput to solve an existing
performance problem, see especially the following papers about performance-problem
resolution using SAS logs in combination with host monitors. Select
Performance
monitoring and troubleshooting to access the following
papers:
-
Solving SAS Performance
Problems: Employing Host Based Tools
-
A Practical Approach
to Solving Performance Problems with SAS
-
SAS Performance Monitoring
- A Deeper Discussion