[comp.unix.questions] Several questions

mtsu@blake.acs.washington.edu (Montana State) (03/24/89)

OK, here are what I hope some simple questions, if they're RTFM then
somebody tell me where.

1)  NFS is supposed to be a "stateless" protocol.  What good is a stateless
protocol that requires  a whole schmeer of stateful servers to  provide
"most" of the semantics of the Unix file system?  I'm thinking specifically
of all of Sun's quotadaemons, lockdaemons, etc etc. ad nauseum.

2)  If I have a 'quota' partition on one machine (machineA)  which is
NFS mounted on machineB, will write()'s done by the user on machineB fail
if the user is over-quota on machineA where the quotas are kept??  I tried
it a few times, and it appears to be that way, but is this behavior 
guaranteed??

3)  If I have a disk partition mounted ro (read-only) and then I want
to remount it rw (read-write)  how do I find who has an open file on that
partition that's keeping me from doing a umount on it.  (Short of shutting
the machine down).

4)  Does doing a full backup, newfs, and a full restore really accomplish
anything constructive? (Short of testing MTBF's for tapes and drives??).

5)  Does the out-of-band signaling part of the Ultrix networking software
work??  I'm not having much luck. 

gwyn@smoke.BRL.MIL (Doug Gwyn ) (03/24/89)

In article <1316@blake.acs.washington.edu> icsu6000@caesar.cs.montana.edu (Jaye Mathisen) writes:
>1)  NFS is supposed to be a "stateless" protocol.  What good is a stateless
>protocol that requires  a whole schmeer of stateful servers to  provide
>"most" of the semantics of the Unix file system?

By not having to propagate revised state information around to all users
of a file whenever any one of them makes a change, supposedly efficiency
is improved.  Also, core NFS deliberately lacks some UNIX file system
semantics to make it compatible with non-UNIX file systems, MS-DOS in
particular.

In a UNIX environment, I agree with your implication that the RFS
(stateful) approach is generally better.  I especially like RFS's
preservation of device driver semantics across multiple hops.  I never
did hear how AT&T was going to solve the problem of ioctl data format
incompatibility among heterogeneous systems, though.