This chapter is a continuation of Chapter 6, Network Lower-Level Protocols, and covers several common application-level network protocols, including HTTP and Network File System (NFS). Using DTrace, you can answer questions about application protocols such as the following.
• What NFS clients are performing the most I/O?
• What files are NFS clients performing I/O to?
• What is the latency for HTTP requests?
These can be answered with DTrace. As an example,
nfsv3rwsnoop.d is a DTrace-based tool to trace NFSv3 reads and writes on the NFS server, showing the client and I/O details:
Although network sniffing tools can ...