🚀 go-pugleaf

Why is NFS so slow?
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  I followed the initial discussion in this group about RPC, TCP, and
UDP with great interest. At about the same time, a friend did a series
of benchmarks in a network of Sparcstation 2's, to compare the file
transfer performance using TCP sockets, NFS (write to remote-mounted
disk), and RPC using TCP. The files were large (around 2 MB or larger).
RPC using TCP was slightly slower than straight sockets using TCP, as
expected. What was surprising was that it was so slow to just do a
large write to the open file descriptor of a remote mounted file.

  It turned out to be much faster to:

  - have a small server process on the remote machine open a file there
  - transfer the file to the remote process with RPC or socket
  - have the remote process write to the file

  Some improvement over the open/write to the remote file was obtained
by mmapping the remote file instead, but this is still slower than using
the remote process.

  Can NFS be tweaked for better performance? Are there other settings
that affect NFS performance this drastically?

  Thanks for any clues!

Rob



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| Rob Weltman                               |
| Xerox                                     |
| 3400 Hillview Ave, building 5             |
| Palo Alto, CA  94303                      |
|                                           |
| weltman@adoc.xerox.com                    |
| phone (415)-813-7477   fax (415)-813-6792 |
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