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 Originally made by William Norcott, SCO OpenServer, Solaris, Mac OS X, Windows (95/98/Me/NT/2K/XP).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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CPU cache effect Buffer cache effect Mwsord measured The graph above shows single stream performance where file size and request size are changed. These are read offset latency, write offset latency, rewrite offset latency and reread offset latency. The reread latencies are clearly not the latencies that one would get if the reads actually went to the NFS server and back.

Here the graph is showing the throughput performance as a function of processes and number of disks participating in a filesystem. This option allows one to override the default and to use multiple internal buffers.

What is “iozone”

The following are some graphs that were generated from the Iozone output files. Another example is when the filesystem is mounted from a remote machine. Excel graphs empty cells as containing a zero. Before you run Iozone please read the run rules at the bottom of this document. This is a classic example of tuning for a specific application. This option ioxone useful if one has taken a system call trace of the application that is of interest.

Only available on some platforms. Most operating systems do not detect this behavior or implement any techniques to enhance the performance under this type of access behavior. Many operating systems have tested and tuned the filesystem so it works well with databases. Iozone Filesystem Benchmark IOzone is a filesystem benchmark tool. The first field is the name of the client. This test measures the performance of writing a new file. Another type of graph that can be produced is the Latency graph.


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One can see from the data the impacts of the extent allocations for extent based filesystems with this option. When a file is written that already exists the work required is less as the metadata already exists.

This is due to the fact that the buffer cache is now completely full of dirty data that must be written before the buffer can be reused. This is used internally to help speed up the test.

This test measures the performance of reading and writing a file with accesses being made to random locations within the file. One might consider using it before your company purchases its next platform.

It is normal for the performance to be higher as the operating system generally maintains a cache of the data for files that were recently read.

Use —az —i 0 —i 1 instead. This option is deprecated in Iozone version 3. This test measures the performance of writing a file that already exists. This may seem like a strange way to read a file but in fact there are applications that do this. So to get the graphs one needs to scroll down to the Excel portion of the file and graph the data in that section. Including the close helps to reduce the client side cache effects of NFS version 3.


It is not possible to unmount the current working directory as the process Iozone is running in this directory.

There are several sets of graph data. If you don’t know how big the buffer cache is, or if it is a dynamic buffer cache then just set the maximum file size to be greater than the total physical memory that is in the platform. Additional notes on how to make the graphs Iozone sends Excel compatible output to standard out.

This test is only available in throughput mode. The file contains one line for each client. As time rolls on the system administrator may decide that a few more office automation tasks could be shifted to this machine.

What does iozone mean – Definition of iozone – Word finder

In the re-read iozonne graph one can clearly see the client side cache that is in NFS Version 3. It will zero fill this alternate buffer before beginning each test. You may see another plateau if the platform has a primary and secondary processor caches. One will always need to specify 0 so that any of the following tests will have a file to measure.

Stonewalling in throughput tests to eliminate straggler effects. When running throughput tests this option allows the user to specify the greatest number of processes or threads to start.