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August 31st, 2016 12:00
math.spatial.sum() inconsistency in formula
Is anyone aware of any sort of alignment of data points that needs to happen in the background for the math.spatial.sum() formula to work ?
I recently changed my performance data collection cycle for VNX to 15 minutes from 5 minutes(default). A day later my reports started showing blank data. (I am running a custom VNX Storage Pool Subscription report)
I found that these were the values where the math.spatial.sum() formula was used to sum the capacity of all the LUNs belonging to a pool.
When I drill down to the individual LUNs I can see the capacity being reported for the individual LUNs. I am clueless as to why this is happening, and its only affecting the VNX arrays which has over 1000 LUNs.
isakats
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September 1st, 2016 07:00
Hi Littlefinger,
This is could be caused by missing data points or by not recovering any values in the time range.
You should review the Time Management setting of the column and see if you are recovering the last value only or all the values in the time range. Arrays with a thousand luns and more will take longer to poll, if you are reporting on real time data and only recovering the last value with a time threshold of 600 seconds...it is possible that some data point are out of the time range of the column.
You can also look into adding a util.MakeRange formula in the child node.
This formula ensures that there is a value for each point of the specified period.
For a given timestamp, if there is no value in the input, it takes the closest one available before, or after if there was none before. It is particularly useful to ensure that relatively infrequently polled metrics aggregates correctly with each other.
You can review the following report report as an example (the path is in edit mode) : All>>EMC VNX>>Summary>>Array Summary>>Array Summary - hidden>>datatype,serialnb (Block)>>device>>Raw Capacity Usage>>Raw Capacity Usage>>Configured Usable>>Arrays
Regards,
Isaka
nerdnair
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68 Posts
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September 1st, 2016 12:00
Hello Isaka
Your suggestion did help, I was reporting the last vaule, for 8 periods in an hour. The report displayed data when I selected all values in the time range.
However as you suggested the root cause of the problem was a longer polling cycle and that the collector was timing out before the entire performance data collection was completed, I had to modify the timeout values within the parser-vnblock-performance.xml file to get the data collection sorted out.
The report is working well now, thanks a lot for your inputs.