Hi,
We are using linuxmeminfo sensor, however the available memory seems to be showing wrong values.
eg: Available Memory is shown as 351MB, when in fact it is 5.7G. It is taking from free rather than available.
$ free -h
total used free shared buff/cache available Mem: 7.6G 1.7G 351M 30M 5.6G 5.7G Swap: 2.0G 34M 2.0G
more /proc/version
Linux version 3.10.0-229.14.1.el7.x86_64 (builder@kbuilder.dev.centos.org) (gcc version 4.8.3 20140911 (Red Hat 4.8.3-9) (GCC) ) #1 SMP Tue Sep 15 15:05:51 UTC 2015
Is this expected functionality or error in sensor.
thanks
Article Comments
The values displayed by the sensor are correct, but please mind that they only consider real free memory while not taking in account cached and buffered memory.
For alternate readings, please use the SNMP Library Sensor with the Basic Linux Library.
Another alternative is to deploy the SNMP Custom Sensor or SNMP Custom Advanced Sensor using one of the following OID's:
| Description | OID |
|---|---|
| The total amount of swap space configured for this host | 1.3.6.1.4.1.2021.4.3.0 |
| The amount of swap space currently unused or available | 1.3.6.1.4.1.2021.4.4.0 |
| The total amount of real/physical memory installed on this host | 1.3.6.1.4.1.2021.4.5.0 |
| The amount of real/physical memory currently unused or available | 1.3.6.1.4.1.2021.4.6.0 |
| The total amount of memory free or available for use on this host | 1.3.6.1.4.1.2021.4.11.0 |
| The total amount of real or virtual memory currently allocated for use as shared memory | 1.3.6.1.4.1.2021.4.13.0 |
| The total amount of real or virtual memory currently allocated for use as memory buffers | 1.3.6.1.4.1.2021.4.14.0 |
| The total amount of real or virtual memory currently allocated for use as cached memory | 1.3.6.1.4.1.2021.4.15.0 |
With both of the above mentioned sensor you should be able to get all memory related information.
Additionally, if you need to see values in Percent, set-up an Sensor Factory Sensor to perform the required mathematical operations on top of the results of the SNMP sensors.
Dec, 2015 - Permalink
yes, this is useful, however we are interested in percentages as absolutely values are not useful.
Do you have any other alternative to get the same values mentioned above as percentage (i.e use out of box and doesn't require to install any scripts).
i.e:
- Available Swap Space %
- Total RAM used %
- Total RAM Free %
- Total RAM Shared %
- Total RAM Buffered %
- Total Cached Memory %
Thanks
Dec, 2015 - Permalink
Have you tried using the standard SNMP Memory Sensor?
The main difference is that while the SNMP Linux Meminfo Sensor queries the 1.3.6.1.4.1.2021.4.xx OID's from the UCD-SNMP-MIB the SNMP Memory Sensor queries the hrStorageTable from the HOST-RESOURCES-MIB, which will most likely display different values.
If that doesn't show you the expected/desired result, the only remaining option which doesn't involve scripting involves using the Sensor Factory Sensor to convert the SNMP values from other sensors to a result in percent.
Best Regards,
Dec, 2015 - Permalink
Hello nkarnati,
we appreciate your contact.
Please download our latest SNMP Tester, run it on the PRTG Host (or host of the Remote Probe), and perform a Walk against the target device providing the "1.3.6.1.4.1.2021.4" OID (without quotes) as parameter.
Which results do you get in the Tester? Please report back with the results from the tester.
Best regards,
Dec, 2015 - Permalink