@gehtmaguad wrote:
Whats the correct way to calculate the Latency of a Volume?
I use the following to get the Latency and IO Counter for Write Requests:
<?xml version="1.0" encoding="UTF-8"?>
<netapp xmlns="http://www.netapp.com/filer/admin" version="1.19">
<perf-object-get-instances>
<counters>
<counter>write_latency</counter>
<counter>write_ops</counter>
</counters>
<objectname>volume</objectname>
</perf-object-get-instances>
</netapp>
Therefor I get the two requested values:
<counter-data>
<name>write_latency</name>
<value>723389447741</value>
</counter-data>
<counter-data>
<name>write_ops</name>
<value>804869240</value>
</counter-data>
From here: How can I calculate the Latency in Milliseconds ?
write_latency is listed as an average in microseconds with the base counter of write_ops.
You'll need to take two samples. Assuming T1 < T2:
(T2.write_latency - T1.write_latency) / (T2.write_ops - T1.write_ops)
That will be in microseconds. Multiply by 1000
.