Disk and Application I/O Profiles

An "I/O Profile" reflects the particular I/O operation activity, patterns, and performance associated with a specific application, workload, system, file or device. I/O Profiles have traditionally been based upon a rather limited set of standard I/O metrics, such as average and maximum IOPS, MB/s, and response times along with total I/O operation counts, data transferred amounts, and read/write ratios.  Queue depth and several specific data transfer sizes (such as 4K, 64K, and 128K) are also often referenced.  Random/sequential access ratios might be mentioned as well.

Notably these types of metrics are stated in device performance claims by vendors and within various performance test-tool and reviewer reports.  Usually these claims and reports are accompanied by the admonition (if not caveat) that the user should also ultimately consider their own actual I/O Profiles.  Exactly how the user determines their particular I/O Profiles is essentially left as an exercise for the user.

A primary goal of the hIOmon software and services from hyperI/O is to help a variety of users easily and quickly determine their particular I/O Profiles.  Moreover, hIOmon enables these I/O Profiles to be established upon empirical metrics that it has captured and which reflect applications, workloads, devices, and the system in everyday usage.  These empirical metrics are based upon actual observations taken at points within the operating system where the individual I/O operations are processed.

The hIOmon ETW I/O Monitor software component leverages the Microsoft® "Event Tracing for Windows (ETW)" facility for obtaining these observations.  Designed and implemented by Microsoft, the ETW supports use within production environments.  It is included within the various Windows operating system versions supported by the hIOmon software.

hIOmon also introduces new, additional metrics such as the hIOmon "Performance Threshold Range Metrics" and the "DataTransferred / Time Index (DXTI)" metric.  These novel metrics allow hIOmon to provide users with broader, more precise, and more pertinent I/O Profiles.

The hIOmon "Performance Threshold Range Metrics" are a large, robust set of automatically-summarized I/O operation performance metrics.  They can be aggregated and displayed in real-time without requiring the separate collection and post-processing of individual I/O operation trace records, which often can be generated in huge quantities. The Performance Threshold Range Metrics are specifically focused upon the ranges of I/O operations per second (IOPS), megabytes-per-second (MB/s) data transfer rates, response times (RT), I/O operation queue depths/lengths (QD), and data transfer sizes/lengths (DTS) actually observed by the hIOmon I/O Monitor for individual devices, files, and processes.

For example, one Performance Threshold Range Metric is the "IOPS 1 - 99" Range Count metric for read I/O operations.  This metric reflects the number of one-second intervals during which the hIOmon I/O Monitor actually observed a total number of monitored read I/O operations that was one or more, but less than 100 read I/O operations.

Similarly, the "MBS 10 < 20" Range Count metric for write I/O operations reflects the number of one-second intervals during which the hIOmon I/O Monitor actually observed a total amount of data transferred by write I/O operations that was 10 000 000 bytes (i.e., 10 megabytes) or more, but less than 20 000 000 bytes (i.e., 20 megabytes).

Click here for screenshots of the hIOmon Disk I/O Ranger Display that illustrate several of the Performance Threshold Range Metrics.

The hIOmon "DataTransferred/Time Index (DXTI)" is a simple, straightforward metric.  It provides a "high-level" means for relative comparison of I/O operation performance, where basically "higher is better".  That is, the "higher" the Index number, the better the performance – as in more data transferred and/or less required response time (i.e., application wait).

The DXTI metric (which can be provided by hIOmon upon an individual file, device, and process/application basis) resembles the "fuel economy" index for an automotive vehicle (i.e., "miles-per-gallon") as an overall measure of "performance efficiency".  It is akin to more miles driven (more data transferred) for fuel used (response time taken to transfer this data), or similarly, same miles (data transferred) but less fuel used (less response time).

As an important component of the I/O Profile, the DXTI metric can be used as a "leading indicator" of overall I/O performance.

The hIOmon Disk I/O Ranger Display highlights the calculated DXTI metric values in yellow text.  Similarly, DXTI metric values are prominently shown within the display header of the hIOmon I/O Trender Display.

Click here for additional information about the hIOmon DXTI metric.

Bringing Transparency to Disk I/O Performance℠