[Info-vax] Mounting NFS disk with /DATA non-default parameters

[glen herrmannsfeldt]

Sum1 <not at here.com> wrote:
>> tcpip sho ver
 
>  HP TCP/IP Services for OpenVMS Alpha Version V5.6
>  on an AlphaServer DS10L 466 MHz running OpenVMS V8.3
 
> Doing a TCPIP MOUNT blah will give a default read/write size of 8192 
> according to TCPIP HELP MOUNT /DATA.  If I want to increase the size of 
> the chunks transmitted, I expect that I can issue a TCPIP MOUNT/DATA=X, 
> where X is some multiple of 512.  If I did /DATA=16384, I expect that I 
> will be transferring 16k chunks.

As well as I understand it, yes, you can do that. 

Are you using UDP or TCP?
 
> The server and VMS client are connected on a Gigabit switch, the VMS 
> client is connecting at 100Mbit/Full (according to LANCP) with a buffer 
> size of 1500.
 
> Will changing NFS data size provide an improvement in transfer speeds?  
> The NFS Server is happy for me to vary the data size???.

NFS, at least the Sun version, does read ahead to keep data ready
to send. As far as I know, there are diminishing returns with the
increased size. There is some overhead for each block, but it isn't
so big as to make a big difference. Also, there is increased
latency for the whole block to arrive. 

Going to jumbo packets might be more useful.

-- glen