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NFS server to client proxy access

 
Buckethead
Occasional Contributor

NFS server to client proxy access

Hi.

I'm setting up NFS server to client connectivity between 2 non-cluster VMS systems.
So far I've mapped the device, did the export but I'm stuck at supplying a UID and GID. On both the server and client there is a normal, priv'd. VMS account I want to use but when I try setting up the proxy it doesn't seem to like what I supply.
Any suggestion on what UID and GID to use?
Rangers Lead The Way
3 REPLIES 3
Hoff
Honored Contributor

Re: NFS server to client proxy access

Go read these two articles for some Unix background on NFS:

http://linuxgazette.net/issue31/tag_uidgid.html
http://www.troubleshooters.com/linux/nfs.htm

That's definitely not VMS, but those to will explain what going on with the ID mapping fairly well.

The VMS mapping is described in various places including the "How the Server Maps User Identities" section in here:

http://h71000.www7.hp.com/doc/83final/6526/6526pro_049.html

The UID and GID values are a functional and necessary and somewhat ugly hack. It's a form of hand-done, hand-waving that provides the mapping of identities across disparate hosts and host operating systems.

It provides the mapping the identity of a user on the NFS client to the appropriate matching identity on the NFS server.

Do avoid the predefined UID and GID values within NFS, with whatever mapping you choose. Otherwise, well, set up whatever mapping is locally appropriate.

If there was enough foresight to use the same UICs on both boxes, you could use that. Otherwise, well, NFS provides a path out of the identifier mess that would arise should you later join these two boxes into a VMS cluster would encounter. Here's a high-level overview of identifiers on VMS, and rationalizing the assignments.

http://labs.hoffmanlabs.com/node/533
http://labs.hoffmanlabs.com/node/169

The UID and GID mapping values are how NFS deals with this requirement for rationalization of these values...
Buckethead
Occasional Contributor

Re: NFS server to client proxy access

Hoff:

Thanks for taking the time to reply. I do understand what the GID and UID are for. I'm just not sure what values to insert here because I'm trying to use one VMS system as the server and another VMS system as the client thus, no disparate file or operating systems.

And I'm assuming the problem I'm having on the client-side - error mounting _dnfs%:[000000] device timeout - has to do with this proxy access between nodes and not something else.

Thanks again.
Rangers Lead The Way
Hoff
Honored Contributor

Re: NFS server to client proxy access

You can use a badge number for the organization, an incrementing integer counter from some central data file or from somebody's office whiteboard, a unique random number within the supported range, or whatever is deemed appropriate to uniquely identity the user in the network.

Same for the group id.

There's nothing special about the values, any more than there's anything special about the UIC value behind a VMS username. (The VMS username-to-UIC mapping scheme is a very similar identity-mapping scheme.)

If you want somebody to pick a value for you, well, start your users at 101, and start your groups at 101, and increment by one for each user or each group you add.

As for the error...

If the NFS client and the server are both on VMS, then ensure that both the client and the server have been fully configured; you can't skip the manuals nor the manual set-up nor tweaks to the configuration files on VMS, and that your DNS is correct, and that you have IP connectivity through whatever VLANs or firewalls might exist here. More often than not, the usual errors here are a failure to configure and start both the client and the server.

Read through chapters 22 and 23 here:

http://h71000.www7.hp.com/doc/83final/6526/6526pro_049.html

if the NFS server is NOT on VMS, then the usual triggers (beyond the above-mentioned options, and such things as firewalls) are that the server isn't serving NFSv2, and all but the most recent TCP/IP Services versions require that NFS version.

When you are working with (I presume) TCP/IP Services, you must read through and follow the configuration sequences. Unfortunately, VMS requires you to have to have the documentation handy, and to manually create or manually update the configuration files in a text editor based on the documented sequences.