Rob won't come right out and say it, so I will.  Contact Velocity
Software and see what kind of terms they'll give your for evaluating
their software.  That will help you diagnose just what is going on with
your situation.

Absent of that, some questions that come to mind are:
Are the source and target file systems on the same DASD
device/CHPID/whatever?
What is the MTU size on your network interface on the VSWITCH?
I'm not a TCP/IP expert by any means, but I believe there are some
"window" values that can be massaged.
Take a look at a VM-only GuestLAN setup for inter-guest communications,
particularly if the MTU size of your LAN is pretty small.
How much real storage does z/VM have allocated to it?
Is any of that storage configured as expanded storage?  If not, it
should be. 
How much virtual storage is being allocated to the 2 Linux guests?
Have you tweaked the z/VM SRM parameters to be more friendly to a Linux
workload?  z/VM defaults them for a CMS workload.


Mark Post

-----Original Message-----
From: Linux on 390 Port [mailto:[EMAIL PROTECTED] On Behalf Of
Peggy Andrews
Sent: Thursday, May 18, 2006 11:02 AM
To: [email protected]
Subject: Re: Poor transfer rates between z/VM Linux guests on VSWITCH

Hi, all.

Given recent events (the new "who's been reading our list"), I'm
hesitant on posting all information here, but I still have a problem
with this transfer performance on our z/VM Linux guests.

For background, we are a government shop with a pretty small z800 box.
We have a single IFL engine and have installed z/VM and Linux guests to
experiment/test Linux.  Like many others, we are very excited, and as
long time z/OS systems programmers, stand strong in our support of the
strengths of the mainframe.  Now we are moving on to a serious
proof-of-concept and are stumbling on this basic test against our
distributed counterparts.

We have reviewed previous suggestions from this thread and made some
adjustments to our testing scenario, but are seeing the same slower ftp
transfer rates from zLinux to zLinux guest on VSWITCH than zLinux guest
to x86Linux.  Also, a copy of the file from one directory to another on
the same Linux instance was slower on the zLinux guest than on the
x86Linux server.

Given that we have little experience here with VM and minimal
training/experience with Linux, I'm confident that we're just missing
something, but I need to figure out what that is.

For minimal "clutter", I can email my testing scenario and results to
anyone interested in assisting us.

Thank you.
Peggy




-----Original Message-----
From: Linux on 390 Port on behalf of Peggy Andrews
Sent: Tue 5/9/2006 10:44 AM
To: [email protected]
Subject: Poor transfer rates between z/VM Linux guests on VSWITCH

We are running Linux guests on an IFL running z/VM

I have two Linux (both SuSE 9) guests defined to the VSWITCH

I have a 684MB file

I use FTP to transfer the file from zLINUX1 to zLINUX2

Results:
1st ftp - 684MB in 2:47 (3.8MB/s)
2nd ftp - 684MB in 1:34 (6.88MB/s)

First question, why is the transfer better on the 2nd ftp of the file?

Then, I attempt the same file transfer from on of my zLinux guests to
an Intel platform Linux server (also SuSE9) on the network (outside of
the IFL).
I use the same 684MB file and use FTP to transfer the file from
zLINUX1
to x86Linux

Results:
1st ftp - 684MB in 1:11 (9.17MB/s)
2nd ftp - 684MB in 1:05 (9.96MB/s)

Biggest question, why is the transfer better going out the OSA adapter
on the network?
I certainly thought the transfer between two guests on the VSWITCH
would have at least been equal if not better??

Any suggestions regarding configuration corrections or troubleshooting
are greatly appreciated.

Peggy


Peggy Andrews
Sr. Systems Engineer
Information Technology Department
Technical Support Services Division
City of Sacramento
(916) 808-5438

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Peggy Andrews
Sr. Systems Engineer
Information Technology Department
Technical Support Services Division
City of Sacramento
(916) 808-5438

----------------------------------------------------------------------
For LINUX-390 subscribe / signoff / archive access instructions,
send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or
visit
http://www.marist.edu/htbin/wlvindex?LINUX-390

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send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit
http://www.marist.edu/htbin/wlvindex?LINUX-390

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