Monitor perf counter change rate (tune up reply value)

bmekler · Post by **bmekler** » Mon May 21, 2012 11:52 am

Sorry about the barrage of questions, we just bought HostMonitor and I'm deploying it across a bunch of systems.

I'm trying to monitor the change rate of a performance counter, and I need to log the change rate rather than absolute values. However, when I set the test to check increases/sec, it still displays and logs the absolute value. I tried to use the "Tune up Reply value" option to manually process the difference, but I've ran into a couple difficulties.

1. Performance counter returns value with two decimal places, which cannot be processed by macro operators. %SuggestedReply_Integer% solves this problem for current value, but there is no such option for %LastReply% or %SuggestedLastReply%. I kind of sidestepped it by using ('%SuggestedLastReply%' getword 1), which returns everything before the period, but I'm not sure it's the optimal solution.
2. I can't find a variable that will give me the number of seconds elapsed since last test. %Interval% simply gives the HH:MM:SS value assigned to the test, and can't be used in calculations anyway. I can set a static number of seconds, but this will not take into account manual refreshes, timeouts, etc, resulting in inaccuracies. Am I missing something?

KS-Soft Europe · Post by **KS-Soft Europe** » Mon May 21, 2012 12:14 pm

1. Performance counter returns value with two decimal places, which cannot be processed by macro operators. %SuggestedReply_Integer% solves this problem for current value, but there is no such option for %LastReply% or %SuggestedLastReply%. I kind of sidestepped it by using ('%SuggestedLastReply%' getword 1), which returns everything before the period, but I'm not sure it's the optimal solution.

If there is the same decimal separator set on HostMonitor system and returned by Performance counter, you may use %SuggestedLastReply% macro variable in quotes like: ['%SuggestedReply%' - '%SuggestedLastReply%']

2. I can't find a variable that will give me the number of seconds elapsed since last test. %Interval% simply gives the HH:MM:SS value assigned to the test, and can't be used in calculations anyway. I can set a static number of seconds, but this will not take into account manual refreshes, timeouts, etc, resulting in inaccuracies. Am I missing something?

HostMonitor also supports %Interval_Sec%, %Interval_Min% variables. They represent the period of time between two consecutive checks defined for the test in minutes and seconds correspondingly and can be used in expressions. However they represent static value, set for the test.

bmekler · Post by **bmekler** » Mon May 21, 2012 12:33 pm

%Interval_Sec% works, I guess. The potential inaccuracies aren't terribly important. Why does increases/sec work differently for performance counters and SNMP GET requests though? I'm using SNMP GET requests to track IOPS on NetApp filers without any issues or tune up tricks.

KS-Soft · Post by **KS-Soft** » Tue May 22, 2012 1:10 pm

Why does increases/sec work differently for performance counters and SNMP GET requests though?

Probably because many of Performance Counter objects offer relative counters like Interrupts/sec, Disk Writes/sec and so on.
While SNMP agents much more often provide just current status. This way its more important for SNMP Get test to show relative value retrieved by calculations within HostMonitor code, while Performance Counter test usually need to show value "as is"

Regards
Alex