IO Input Output Metric in Dynatrace Reports
Hi All,
Can you please guide me to i/o metrics chart by Dynatrace.
I have checked in Charting/Diagonose events section and I am unable to get it there.
Dynatrace Server version : 3.2
Your help is appreciated.
Regards
Shahab
Hi Shahab,
What do you mean by i/o metrics? Can you give an example?
Looking at our internal systems you are on 4.2, which is the current version - not 3.2 which would be almost 3 years old. Can you confirm?
Best, Roman
Hi Roman,
The server version is still 3.5.2 (sorry for the typo in earlier message)
We have a upgrade to version 4.2 pending in CMIC env.
At this moment the Client version is also 3.5.2
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We want to measure the time a process is taking in i/o operations like file handling, database operations. The metrics we want is specific to I/O related timings.
We were interested in knowing if such metrics is available in Dynatrace.
My other Question is
Can we use (EXEC time - CPU time) to calculate the I/O time. Will that be a right approach ?
Thanks for clarifications.
Regards
Shahab
Hi Shahab,
In order to get better insight into how much time an app spends with I/O operations I strongly recommend upgrading to version 4. The new auto sensors will allow you to see where the app spends time down to the low level I/O methods. This visibility is necessary to for example to distinguish if a database call was waiting on the network (I/O time), just processing the incoming data (CPU time) or suspended because of a garbage collection running.
There is a new view called response time hotspots, which I think is what you are looking for. It gives a breakdown of the time spend by an agent into 5 categories: CPU, I/O, Wait, Sync and Suspension. Keep in mind that dynaTrace agents capture this data for PurePaths - so if you have activity on the JVM (or CLR) that is not covered by a PurePath it will be missing from this breakdown.
Exec time - CPU time won't work because the difference is a mixture of I/O, wait, sync and suspension time.
Best, Roman
Dear Roman,
Thank you very much for the information and clarification. I have forwarded request for Dynatrace upgrade at CMIC and i will check out the I/O Metrics in the upgraded version.
Regards
Shahab
Hi,
Please tell me where in documentation/online i can find exact formula used to calculate CPU% and IO% that shows up in Breakdown column of Purepaths chart. Please see attached pic.
Thanks
Hi
When a PurePath is executed we capture CPU time used by the threads that are executing this transaction. Thats how we know how much of the total Response Time of a PurePath is actually spent on the CPU. We also capture the information on how much time was spent in Sync (sync blocks), Wait (waiting on an object) and Runtime Suspension (thats when the GC kicked in and paused the thread). The rest of the time will be contributed to I/O.
So - the formula goes like this
Response Time = CPU + Sync + Wait + Runtime Suspension + I/O
or better
I/O = Response Time - CPU - Sync - Wait - Runtime Suspension
As I mentioned above. We do not really capture I/O time - but this is the one value we really "calculate". For all others we have a way to measure it
Does this help? If so - I will make sure to also add this to the documentation
Andi
Thank you very much. Adding this info in documentation will help others in future.
Regards
Shahab
Hi!
I added the info to Response Time Hotspots and put a reference to PurePaths there where this is discussed in more detail.
Thanks for pointing this out!
G.
