Some additional networking tests that might be revealing:

FTP from zLINUX2 to zLINUX1
FTP from x86Linux to zLINUX1 and
FTP from x86Linux to zLINUX2.

These tests might reveal if there is something different between the two
Linux guests and help to focus on which might be having the problem.
The tests presented in your email make the implicit assumption that the
two Linux guests are operating the same and this may not be the case.
If the slowest transfer rates are always between the two Linux guests,
resource contention might be a good path of research.  If one performs
better than the other, look for why they are different.

Also, do a traceroute from zLINUX1 to zLINUX2 and from zLINUX2 to
zLINUX1.  The traceroute will ensure that there are no unexpected
network paths coming into play for packets flowing in either direction.
There should be no hops between the two zVM Linux guests.  The
traceroute tests verify that VSWITCH is operating as you think it is.

Some simple tests can be performed using ping options (set various
payload sizes and do-not-fragment IP options) to verify MTU.  These
should likewise be performed from and to each Linux guest.  MTU's must
be the same for both Linux guests' VSWITCH interfaces to avoid
fragmentation and reassembly.

Assume nothing and verify everything.

Harold Grovesteen


Peggy Andrews wrote:

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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