Conference 7.286::fddi

2232.0. "FDDI, PATHWORKS and NT Server" by 52200::peoto.soo.dec.com::ptorlind () Wed Feb 26 1997 05:23

Hello !!

This was cross posted in PWV50IFT Conf !!



I need some advice on a performance issue at a customer site, what 
side to trouble shoot !! This is the case...

Customer has 1 Alpha 4000 with 512MB mem, VMS 7.1, UCX 4.1-ECO2
PW 5.0E and 2 Prioris ZX with double CPU's and a lot of
memory running NT 3.51.
The A4000 is using DEFPA fddi interface, the Prioris i don't know 
yet.

These system are connected to and FDDI ring, and customer is
experiencing that file copy is slow to and from vms and nt.
Protocol is TCP-IP only. No clients connected on no other activity on
system.

This is what we tested with a 5MB text file, copy using the File
Manager in NT.

Copy file --> NT to NT   2-3 seconds
              NT to VMS  15-20 seconds
              VMS to NT  35 seconds  ( using File Manager on the
                                           receiving NT server)
              VMS to VMS 4-5 seconds (using DECnet, only for test)
              VMS to VMS (FTP) 2 seconds
              NT to VMS (FTP)  5 seconds
              VMS till NT (FTP) 12 seconds


We tested doing the same thing but off the FDDI, on a Ethernet 
segment instead using an AXP150 with VMS 7.1, PW 5.0E, UCX 4.1 
and an Celebris GL as an NT server.

When copy the same file from NT to VMS it took about 23 sec
and from VMS to NT about 21 seconds.

So, what we can see here is that on the FDDI, when involving 
PATHWORKS in the file transfer, the performance decreases a 
lot. Without PATHWORKS performance is OK.

Anyone have any hints in what direction to start ??
Could TCP Window Size on the NT server improve anything ??
UCX tuning on the VMS side ??

I'm going to enable debug mode on the vms server and check the logs.
If anyone have any ideas at all i will be thankfull.

----------------------

Since then we did 

$ UCX SET PROTOCOL TCP /NODELACK
$ UCX SET CONFIG PROTOCOL TCP /NODELACK


That made the copy from NT to VMS/PW take 2 seconds, so that
solved it one way. It still takes 35 seconds from VMS/PW to NT.
The DEFPA NT drivers has been changed to the lates ones also.

Anyone have any clue where or what to do.

Per Torlind / PATHWORKS support, Sweden

Hi again !!

Update to .0

By setting TcpWindowSize on the NT server everything started
to work just fine.


Case closed


Per Torlind / PATHWORKS support, Sweden