The Geneos Device IO Plug-in reports disk activity. This information is published by the kernel enabling the plug-in to produce highly accurate measures of throughput, utilisation, queue lengths, transaction rates, and service time. Each row in the table displays a device mounted on that disk.
The Device IO plug-in is only supported on Linux and Solaris platforms.
On Linux Netprobe versions 3.0.21 and up, the Device IO plug-in extracts its data from the operating system data sources file:
- DiskStats —
- SysFs —
- Partitions —
- StatFile —
This plug-in extracts the data in order. For example, the Device IO plug-in looks for DiskStats first. If DiskStats is not available, then it looks for SysFs and so on.
The Device IO produces a single view for Solaris as follows:
|Device||The name of the actual device|
|readRate||Reads per second|
|writeRate||Writes per second|
|readRateKB||KB read per second|
|writeRateKB||KB written per second|
|aveTransWaiting||average number of transactions waiting for service(queue length)|
|aveTransActive||average number of transactions actively being serviced (removed from the queue but not yet completed)|
|aveServiceTimeMs||average service time, in milliseconds|
|percentWait||percent of time there are transactions waiting for service (queue non-empty)|
|percentBusy||percent of time the disk is busy (transactions in progress)|
The Device IO plug-in produces the following view for Linux:
|activeSegments||The number of devices.|
|device||The name of the actual device.|
|readRate||The number of read requests that were issued to the device per second.|
|writeRate||The number of write requests that were issued to the device per second.|
|readRateSector||The number of sectors read from the device per second.|
|writeRateSector||The number of sectors written to the device per second.|
|aveRequestSize||Average size (in sectors) of the request that were issued to the device.|
|aveQueueLen||The average queue length of the requests that were issued to the device.|
|aveRequestTimeMs||The average time (in milliseconds) for I/O requests issued to the device to be served.|
|aveServiceTimeMs||The average service time (in milliseconds) for I/O requests that were issued to the device.|
Percentage of CPU time during which requests were issued to the device.
On Linux Netprobe version 4.x.x or higher, the
Allows the user to specify just those devices they are interested in, as opposed to having statistics displayed for all of the devices found in the system.
Identifies a single device that the user wants to see statistics on. The idea is that the user be able to specify several of these, indicating specifically which devices they are interested in.