Throttle rsync (flie manager transfers) while copying / transfering files to array

Put the following script in your /boot/config/go file or add a script to the Users Scripts plugin and set it to "At First Array Start Only":

This script adds a bandwith limit to all rsync processes as long the destination path of rsync is an array disk. For me 60 MB/s works really good. Feel free to adjust 60000 to your needs. Since I use it, my array is much more responsive while rsync is running.

# -------------------------------------------------
# Throttle rsync transfers to array disks v1.0
# -------------------------------------------------

# rename original rsync
[[ ! -f /usr/bin/rsync.orig ]] && mv /usr/bin/rsync /usr/bin/rsync.orig


if [[ -f /usr/bin/rsync.orig ]]; then

  # create wrapper script
  cat <<'##EOF' | sed -E 's/^ {4}//' >/usr/bin/rsync 
    #!/bin/bash
    # rsync wrapper to throttle transfers to /mnt/diskX

    # Check if destination is an Unraid array disk
    add_bwlimit=
    last_arg="${@: -1}"
    if [[ "$last_arg" =~ ^/mnt/disk[0-9]+ ]]; then
      add_bwlimit=1
    fi

    # Check if --bwlimit is already present
    for arg in "$@"; do
      if [[ "$arg" == --bwlimit=* ]] || [[ "$arg" == --bwlimit ]]; then
        add_bwlimit=
        break
      fi
    done

    # execute rsync with bandwidth limit
    if [[ $add_bwlimit ]]; then
      exec -a /usr/bin/rsync /usr/bin/rsync.orig --bwlimit=60000 "$@" # KB/s = 60 MB/s

    # execute original rsync
    else
      exec -a /usr/bin/rsync /usr/bin/rsync.orig "$@"
    fi

##EOF

  # make wrapper executable
  chmod +x /usr/bin/rsync

fi