2010-06-22 10:02 AM
I am trying to figure out the math to get iSCSI latency. I have the following code to get the raw data but I am trying to figure out the relationship between counters and base-counters
$counters = (Get-NaPerfData iscsi).counters
$counters has values for iscsi_latency (units = ms) and iscsi_ops (units = ops per second) . Also, I have found that iscsi_ops is the "base counter." What post processing math do I need to get iscsi latency in ms?
2010-06-22 10:59 AM
I think I just answered my own question. It looks like the raw numbers do not correspond to the units (aka ops/sec or ms) All i need to do is divide the latency counter by its base counter. This seems to line up with the data we are getting from "My Auto Support."
If I am missing something, please do let me know.
2010-06-22 11:25 AM
Hi, Andy. Yes, that looks correct for an averaging metric such as latency. To measure latency over a specific interval, you can get the values at the start and end of the interval and then use:
average = (counter_t2 - counter_t1) / (base_t2 - base_t1)