Re: NFS server with variable speeds

Olaf Kirch (okir@monad.swb.de)
Tue, 9 Jun 1998 13:03:30 +0200

On Wed, Apr 29, 1998 at 11:32:33PM +0200, Pavel Machek wrote:
> And then there are slow files and slow directories. Reading block from
> slow file can take something like 30 minutes in worst case. Reading
> slow directory will be faster, but it can well take 2 minutes or so.

NFSv3 would help you with this; it is supposed to return NFS3ERR_JUKEBOX
in this case (and then you need a client that can grok this error).

> Question 2 is: what should nfs server do while trying to read block?
> My current version just drops the request...

This service should most likely be used over a TCP connection only.
In this case, you can hook a procedure into the TCP SVCXPRT receive
routine that forks whenever a TCP connection comes in (you'll need
a recent unfsd for this that does work multi-threaded).

Note that you'll run into bad problems with NFS clients, though. I
don't think that there are NFS clients that will easily tolerate
round-trip times of 2 hours...

Olaf

-- 
Olaf Kirch         |  --- o --- Nous sommes du soleil we love when we play
okir@monad.swb.de  |    / | \   sol.dhoop.naytheet.ah kin.ir.samse.qurax
okir@caldera.de    +-------------------- Why Not?! -----------------------
         UNIX, n.: Spanish manufacturer of fire extinguishers.            


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