iozone benchmark doc. You may use one or more of the following keywords [iozone msword pdf ozone] to. IOzone. IOzone is a file system benchmark utility. Originally made by William Norcott, SCO OpenServer, Solaris, Mac OS X, Windows (95/98/Me/NT/2K/XP). I wrote this book using Microsoft Word 98 for the Macintosh. Hence, the screen shots, menus, etc. might look a little different if you are using a different version or .

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This option allows both types of applications to be simulated. This saves quite a bit of time. This ensures that the entire measurement was taken while all of the processes or threads were running in parallel. Once the total number of cpus is exceeded then future processes or threads will be placed in a round robin fashion.


What is “iozone”

This test measures the performance of reading an existing file. Each line has three fields. If one used the —A option then the area that was not tested would have been tested and had real values. The second field is the path, on the client, for the working directory where Iozone will execute. When testing with unmount between tests it is necessary for the temporary file under test to be in a directory that can be unmounted.

An example of this type of enhancement is: Many operating systems have tested and tuned the filesystem so it works well with databases.

This causes all of the temporary files being measured to be created and accessed with the mmap interface. Processor cache size configurable. This run was taken with the —a option.


The graph above was created by running Iozone multiple times and then graphing mswoed combination of the results. The benchmark generates and measures a variety of file operations.

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This cache can be used to satisfy reads and improves the performance. Once this mapping is in place then stores to this location in memory will result in the data being stored going to a file. Read at offset zero for a length of 4 Kbytes, then seek Kbytes, and then read for a length of 4 Kbytes, then seek Kbytes and so on.

This test measures the performance of writing a file that already exists. The first sub process or thread will begin on the specified processor. The reason that this occurs when the file is bigger than the buffer cache is because the write to the first block on the rewrite case will not find the block in the buffer cache and will be forced to clean a buffer mwword using it. This is a library routine that performs buffered write operations. Such as the point where UFS will allocate its first indirect block.

This test measures the performance of writing a file using the library function fwrite.

The type of graph used is “Surface”. It is normal for the rewrite performance to be higher than the performance of writing a new file. These high latencies can be caused by a variety of causes. During the throughput tests all threads or processes are forced to a barrier before beginning the test.

This may be needed if the client is running NFS version 3. This option should be used in conjunction with the -u option. You may see another plateau if the platform has a primary and secondary processor caches. The latency versus offset information is useful for seeing msworc there are any particular offsets in a file that have high latencies. This test measures the performance of reading a file using the ioone function fread.


CPU cache effect Buffer cache effect Not measured The graph above shows single stream performance where file size and request size are changed. It is normal for the initial write performance to be lower than the performance of rewriting a file due to this overhead information. To graph the data just highlight the region containing the file size and record size and then click on the graph wizard.

Excel importable output for graph generation. Normally this is not a desirable iozpne to test because it is very time consuming to write a MB file in 4k transfer sizes. This access behavior can also sometimes produce interesting performance anomalies.

This is generally sufficient but for some very lozone systems you may need to use the —g option to increase the maximum file size. An example would be if the file size is just a bit bigger than the buffer cache size.

This may be redirected to a file and then processed with Excel. The third field is the path, on the client, for the executable Iozone. To use this option one must be able to execute commands on the clients without being challenged for a password. Examples of running Iozone: The first field is the name of the client.

Here one can see that there are some file sizes and some record sizes that have very bad performance.