Thank you for your response.
The ~80ms latency is maybe average.
I got latency-number by "statistics" commnad, but I couldn't find detail of cifs latency from internal site or documents.
> statistics start -object cifs -vserver svm_ntap1 -sample-id 1
I have already broken a test environment because there was a problem of the cost.
Therefore, I can't run perfstat.
I welcome a release of R3 instance of COT.
But I want to know the reason that R3 instance resolves this write performance issue.
CPU and Network were not bottleneck in write performance, and there was not difference in performance by one disk and two disks.