Making a named pipe over NFS

[michael.d.scheer]

In article <2415 at munnari.oz.au> ok at cs.mu.oz.au (Richard O'Keefe) writes:
>In article <2229 at cbnewsl.ATT.COM>, mdash at cbnewsl.ATT.COM (michael.d.scheer) writes:
>> NFS does not support named pipes, because they (like devices) require
>> state on the server, and NFS servers are stateless.  FYI, RFS (that
>> other distributed file system) does support named pipes.
>
>A Sun-3 client running SunOS 4.0_Export _can_ create a named pipe
>in an NFS file system mounted from a Sun-3 server.
>
>NFS servers don't maintain _connection_ state, but surely the state
>which is relevant to a named pipe is the _contents_.

The NFS server source I've seen returns EISDIR on an attempt to read
other than a regular file, but I suppose that does not rule out
the existence of NFS servers that do otherwise.

The NFS protocol IS designed to support stateless servers, and yes,
that IS statelessness with respect to the FILE.  This is why the
lock manager is a separate network service, not part of NFS.
One happy result of this statlessness is that NFS servers don't
have to do anything if a client crashes.  A less happy result is
that files with inherently stateful semantics (named pipes, e.g.)
have not traditionally been supported by NFS.