MC78 Homework 5 (Fall 1998)
Due: December 4, 1998
NFS (the Network File System) has various parameters the system
administrator can set. One is how large a chunk of data should be
read or written in a single request (i.e., a singe RPC). The maximum
size is 8Kbytes. Which would
typically give better performance: a small value or a large value for
the request size? Why?
Another NFS parameter the system administrator can set is the timeout
time, that is the length of time the client should wait for a response
from the server before retrying the request. First, suppose the connection
to the server is very reliable, but the server is sometimes heavily
loaded. Would you prefer a short timeout or a long one under these
circumstances? Why? Now suppose instead that the connection is
rather unreliable, but the server is generally lightly loaded. Would
you now prefer a short timeout or a long one? Why?
Actually, the timeout length set by the system administrator only is
used for the first attempt to make each request. If the request needs
to be retransmitted, the timeout is doubled the second time, and
doubled again the third time. Explain why NFS is designed this way.
Do exercise 18.7 from page 593.
Instructor: Max Hailperin