parallelize rsync calls using gnu parallel

Question

I am trying to parallelize my rsync calls using gnu-parallel as shown below. But whenever I run my below script, it looks like it doesn't copy anything at all. But I do see lot of rsync processes (ps aux | grep rsync) running so not sure what's wrong here:

export PRIMARY=/data01/test_primary
export SECONDARY=/data02/test_secondary
export dir3=/bat/data/snapshot/20180227
PRIMARY_FILES=(685 959 682 679 688 651 909 906 657 881 884 878 853 707 847)
SECONDARY_FILES=(950 883 887 890 1001 994 997 1058 981 833)

export LOCATION_1="machineA"
export LOCATION_2="machineB"
export LOCATION_3="machineC"

do_Copy() {
  el=$1
  PRIMSEC=$2
  rsync -az golden@"$LOCATION_1":"$dir3"/proc_"$el"_5.data "$PRIMSEC"/. || rsync -az golden@"$LOCATION_2":"$dir3"/proc_"$el"_5.data "$PRIMSEC"/. || rsync -az golden@"$LOCATION_3":"$dir3"/proc_"$el"_5.data "$PRIMSEC"/. || exit 1
}
export -f do_Copy
parallel -j 5 do_Copy {} $PRIMARY ::: ${PRIMARY_FILES[@]} &
parallel -j 5 do_Copy {} $SECONDARY ::: ${SECONDARY_FILES[@]} &
wait

echo "All copied."

Is there anything wrong I am doing here?

Answer 1

You are processing the arguments incorrectly in the do_Copy function that you have defined. Take extra pre-caution in processing positional arguments in shell scripting. Your code just leave one argument from the array in your final command.

You need to use $@ as the complete list of arguments in your function as

do_Copy() {
  (( "$#" )) || { printf 'insufficient args supplied' >&2 ; return 2; }

  el="$1"; shift
  PRIMSEC="$@"

  rsync -az golden@"$LOCATION_1":"$dir3"/proc_"$el"_5.data "$PRIMSEC"/. || rsync -az golden@"$LOCATION_2":"$dir3"/proc_"$el"_5.data "$PRIMSEC"/. || rsync -az golden@"$LOCATION_3":"$dir3"/proc_"$el"_5.data "$PRIMSEC"/. || exit 1
}

and quote the variables when calling the array

export -f do_Copy
parallel -j 5 do_Copy {} "$PRIMARY" ::: "${PRIMARY_FILES[@]}" &

Once you store the $1 in the function, with a first call to shift the rest of the positional arguments are available under "$@" which you originally intended to store.