2008-01-05 02:24:47

by Greg Banks

[permalink] [raw]
Subject: Re: A new NFSv4 server...

Rick Macklem wrote:
>> You had me worried there for a moment, I thought you might be the first
>> person to admit to liking the NFS4 protocol design.
> I actually like quite a bit about it, although I agree that the XDR/Sun
> RPC underpinnings are getting pretty tired (mid-1980s). I liked Sessions,
> but think that it's gotten overly complex (why 5 required encrypted
> checksum algorithms, wouldn't one be enough? for example).

Agreed, the basic ideas behind Sessions are good and long overdue.

> It would have been simpler,
> if it had been "posix only" and not tried to be Windows compatible, but
> I see the argument for Windows compatibility, hense the Open.

I don't see the argument. I've yet to meet a sysadmin who would want
to use NFS from a Windows client when that client already has a adequate
remote filesystem client implementation on it.

>> The classic persistent file handles, for example, could be considered a
>> major
>> design flaw. Firstly it makes the inode# -> dentry lookup a performance
>> path
>> for the underlying filesystem, which it isn't in any local load.
> Sounds like a server implementor's perspective.
Well, yeah ;-)

> From a client implementor's
> point of view, a T-stable file handle is a wonderful thing. I have no idea
> how to correctly implement client side support for the volatile file
> handles allowed in NFSv4. My client doesn't support them.
I can see how volatile file handles would be a problem for clients, and
I don't think they're the answer either. For files, a better solution
would be to use an index into a small per-session table of open files.
Directories are a different matter though.

Greg Banks, R&D Software Engineer, SGI Australian Software Group.
The cake is *not* a lie.
I don't speak for SGI.