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Network Data Copy Tests

The following procedure is used to load the network between the DCM and a buffernode (or master)

On the source machine:

First generate a large file (this produces a 1 GB file on the local shared memory file system:

dd if=/dev/urandom of=/dev/shm/testfile bs=8192  count=131072 >& /dev/null

Next spin up a source port that will feed the file to a client. This incantation does so on port 9333

while true ; do cat /dev/shm/testfile ; done  | ./pv -b | nc -l 9333 > /dev/null

When this starts it will show a byte count of bytes transferred to the pipe. This should start immediately and then block at 64kb (if no one is reading).

Now on the DCM client side:

Start up a client to consume the file over the network:

while true ; do socat - tcp4-connect:192.168.136.16:9333 | pv -b > /dev/null ; done

When this connects it will show a running byte count of byte received. The example is:

[dcm-2-03-01]: while true ; do socat - tcp4-connect:192.168.136.16:9334 | pv -b > /dev/null ; done
10.4GiB

This test can be left running and will just continue to send the file between the two nodes. When the test fails the pipes will stall and you will get a sum of the number of bytes at the time when one of the ends failed.

Network test results

DCM
Diblock Position Transfer Time Notes
3 1 123 GB Time ~ 90min No failure
3 2 123 GB Time ~ 90min No failure