RE: Tweaking FTP file transfers

Based on your comments below, could there simply be paging issues because of
the inordinately large amount of memory being used?

 -----Original Message-----
From:   web400-bounces@xxxxxxxxxxxx [mailto:web400-bounces@xxxxxxxxxxxx]  On
Behalf Of web400@xxxxxxxxxxxxxxxx
Sent:   Wednesday, August 03, 2005 3:44 PM
To:     Web Enabling the AS400 / iSeries
Subject:        Re: [WEB400] Tweaking FTP file transfers


> We have a need to FTP several large files nightly to one of our vendors.
> These files are 350K and up and at times take hours to FTP from our 400 to
> the remote server yet if we place these files on a Wintel box, they'll FTP
> in minutes.

Hmmm... why would it matter whether they're coming from Windows or an 
iSeries?

Have you tested the connection between your iSeries and it's gateway to 
see if you receive packet loss?  A ping flood (during off-hours) might be 
a good test.

If your performance is that much worse than a Windows machine, I'd have to 
assume that there's a hardware problem -- or a gross misconfiguration.


> I'm wondering what on the AS/400 could be tweaked to improve the
> transmission time.  Two things I've been looking at are the TCP send and
> receive buffer sizes which are currently set to 1,000,000 (default value
is
> 8,192).

Although that's a colossal waste of memory, I don't see how it would cause 
slowdowns.  (You do understand that that isn't a system-wide setting, 
right?  It's a per-socket setting. If you have 1000 active sockets, you'll 
have 2gb of memory in use!)

> Also I've found some jobs lingering in QSYSWRK, QTFTPxxxxx which
> run at priority 25.  I could drop the class down to something equal to or
> lower than my interactive subsystem but I'm not quite sure what these jobs
> do and if changing their priority really would do anything.

Those are FTP server jobs.  I understood from your message that your 
iSeries was acting as a client, not a server. If that's the case, those 
jobs are completely irrelevant.

Like I said, I'd be looking for a hardware problem.  (Dropped packets, 
corrupted packets, bad cable) or I'd be looking for a misconfigured 
interface (MTU set too low, duplex set incorrectly, etc)