Unsolved
This post is more than 5 years old
26 Posts
1
2051
Calculate VNX statistics
Hi,
I am trying to figure out how to calculate Service Time and Response Time for Disks, LUNs, SPs etc. on a VNX block-only. I know that these numbers are available through Analyzer, but I would like to avoid using Analyzer.
My plan is to use Navisphere Secure CLI to gather information from our VNX once every minute and then, hopefully, calculate the missing values.
An example would be:
naviseccli -h spa getall -lun
Among others, it will provide values for:
ReadRequests, WriteRequests, BlocksRead, BlocksWritten, LunBusyTicks, LunIdleTicks, NumberOfArrivalsToNonZeroQueue and SumQueueLengthsByArrivals.
From these numbers, I can calculate:
Utilization % = 100 * (BusyTicks/(BusyTicks+IdleTicks))
TotalThroughput = Calculated IOs per second
In the VNX Monitoring & Reporting software, I found the formula for calculating Average Busy Queue Length:
AverageBusyQueueLength = (SumQueueLengthsByArrivals - (NumberOfArrivalsToNonZeroQueue / 2)) / TotalThroughput
I have been able to find information stating that Service Time is calculated from Utilization and Throughput and Response Time is calculated from Utilization, Throughput and AverageBusyQueueLength.
Can someone provide the formulas for calculating Service Time and (average) Response Time ?
Thanks.
- Jimmy
ksnell
38 Posts
2
September 3rd, 2013 01:00
Hi Jimmy.
For the Storage processor:
Service time is 1000 * (Utilization/throughput)
Response time is 1000 * (Queue length/throughput)
Queue is Average Busy Queue * Utilization
For a LUN:
Service time = ((requests_SPA*Service_time_SPA)+(requests_SPB*Service_time_SPB)) / (Requests_SP_A+Requests_SPB)
Response time = ((requests_SPA*Response_time_SPA)+(requests_SPB*Response_time_SPB)) / (Requests_SP_A+Requests_SPB)
The response time will be an average as it's based on the sampling period that you calculate the utilization from (total ticks).
Regards,
~Keith
tmhudg1
20 Posts
0
October 25th, 2013 07:00
Hello,
I have the same need to calculate response time via navicli. This looked to be the solution but I'm having trouble getting the required values to make the calculations. It seems like the getall command doesn't report busy/idle ticks for Pool LUNs. Is that correct? Is there another way to get that info?
Thanks,
Tom