RPC vs Socket

RPC vs Socket

[Blesson Paul]

hi all
                      I am in the way of building  a new remote file system.
Presently I decided to use sockets for remote communication. Lately I
understood that RPC is used in coda and nfs file systems(is it so).  I want to
know the fessibility in using RPC in the new file system.
                      by
                           Blesson Paul

Re: RPC vs Socket

[Trond Myklebust]

>>>>> " " == Blesson Paul <blessonpaul@usa.net> writes:

     > hi all
     >                       I am in the way of building a new remote
     >                       file system.
     > Presently I decided to use sockets for remote
     > communication. Lately I understood that RPC is used in coda and
     > nfs file systems(is it so).  I want to know the fessibility in
     > using RPC in the new file system.

Should be no problem. The RPC layer is not tied to any particular
filesystem.

On the client, you need to set up struct rpc_procinfo with the
necessary RPC XDR routines, which you then declare to the RPC layer
using a struct rpc_program and a call to rpc_create_client(). See
for instance linux/fs/lockd/mon.c, or linux/fs/nfs/mount_clnt.c...

For the server, things are likely to be a bit more complex in that you
need to declare the routines using structs svc_program, svc_version
and rpc_procinfo (again) and then set up a daemon process. Examples of
use include linux/fs/lockd/svc.c and linux/fs/nfsd/nfssvc.c...

Cheers,
  Trond

Re: RPC vs Socket

[Jan Hudec]

>                       I am in the way of building  a new remote file system.
> Presently I decided to use sockets for remote communication. Lately I
> understood that RPC is used in coda and nfs file systems(is it so).  I want to
> know the fessibility in using RPC in the new file system.

Both seem to have pros and cons. RPC should be easier to write (especialy the
server side), but it performs bad with UDP on slow links. (NFS did not work on
115200 serial line because of too many dropped packets - TCP flow control too
badly needed in such cases). Or can linux do RPC over TCP?

For puropose of shool excercise the work saved with RPC might be tha main argument.

--------------------------------------------------------------------------------
                  				- Jan Hudec `Bulb' <bulb@ucw.cz>

Re: RPC vs Socket

[Trond Myklebust]

>>>>> " " == Jan Hudec <bulb@ucw.cz> writes:

     > Both seem to have pros and cons. RPC should be easier to write
     > (especialy the server side), but it performs bad with UDP on
     > slow links. (NFS did not work on 115200 serial line because of
     > too many dropped packets - TCP flow control too badly needed in
     > such cases). Or can linux do RPC over TCP?

The RPC client code for TCP is ready and already working both in
2.2.18+ and 2.4.x.

The server code however needs work.

Cheers,
  Trond

Re: RPC vs Socket

[hugang]

On 23 Jun 2001 17:49:39 +0200
Trond Myklebust <trond.myklebust@fys.uio.no> wrote:
	
> >>>>> " " == Jan Hudec <bulb@ucw.cz> writes:
> 
>      > Both seem to have pros and cons. RPC should be easier to write
>      > (especialy the server side), but it performs bad with UDP on
>      > slow links. (NFS did not work on 115200 serial line because of
>      > too many dropped packets - TCP flow control too badly needed in
>      > such cases). Or can linux do RPC over TCP?
> 
> The RPC client code for TCP is ready and already working both in
> 2.2.18+ and 2.4.x.
> 
> The server code however needs work.

Where can find some document for write rpc program in kernel .

Thanks