Another way to look at the latency times from Envisioning NFS performance is looking at the different layers of the stack we go through.
On the last post, I instrumented the latency data collection at the TCP layer on the NFS server, but there are a lot of other layers.
The are many layers to analyze. I can analyze the NFS server more easily, since at my work, the NFS server is always running Open Solaris thus I have access to dtrace to analyze the latencies. The latencies in the previous blog were at the TCP level on the NFS Server, but that is just one point in the whole stack.
My goal here is to tune to make sure the server is to make sure the NFS server is responding quickly and to detect if there are any network or client issues. I have access to dtrace on the server but the clients can be anything so I have limited access to data from the clients.
Thus my first step is to instrument data collection on the NFS server to make sure it is responding quickly.