[CentOS] Network Performance

Chris Olson
Mon, 30 Apr 2018 17:43:04 -0000

One of our summer interns has stayed on working part time
on weekends during the school year.? This schedule presents
an opportunity for technical investigations and some needed
performance testing.? The last weekend assignment included
data rate testing on one specific network pathway.

Checking out previous network testing was the first assignment.
Some five year old, archived SPARC/Solaris and Intel/Solaris
network tests included ftp runs like the following:

ftp>
ftp> put "|dd if=/dev/zero bs=32768 count=8000" /dev/null
200 PORT command successful.
150 Binary data connection for /dev/null (IP Address).
8000+0 records in
8000+0 records out
226 Transfer complete.
local: |dd if=/dev/zero bs=32768 count=8000 remote: /dev/null
262144000 bytes sent in 23 seconds (11081.79 Kbytes/s)
ftp>

There were dozens of examples of such ftp tests with varying
block sizes, bidirectional transfers, destination files on
RAID storage, and a mix of some system loading programs run
independently and during the network performance testing.
Also archived were a full complement of network tests with
what looks like the original ttcp and possibly newer versions.

These utilities looked like they would work on our CentOS 6
systems, but we did not find ttcp and the ftp tests failed.
the piping from dd failed with a message indicating that:
|dd was not a recognized file.

We no longer have available CentOS systems with versions of
the OS before CentOS 6.? Could there have been a change to
ftp that will not allow a source file specified in this way
or would this transfer method have never worked on Linux?