Improving RAID Initialization and Expansion time on Synology DS418play

SpeedupSynologyExpansion.sh

# Initializing DS418play with 4 x 6TB disks

# ssh to NAS as yourseld

# Check the RAID block device and tunable values

cat /proc/mdstat  # was md2.  Getting about 30M/s

# Get original values:
echo "speed_limit_max: `cat /proc/sys/dev/raid/speed_limit_max`" #=> 200000
echo "speed_limit_min: `cat /proc/sys/dev/raid/speed_limit_min`" #=> 10000
echo "stripe_cache_size: `/sys/block/md2/md/stripe_cache_size`"  #=> 1024

# update to use more RAM (Stripe Cache Size) and higher lower bound (speed_limit_min)
echo 200000 > /proc/sys/dev/raid/speed_limit_min
echo 16384 > /sys/block/md2/md/stripe_cache_size

cat /proc/mdstat  # Now Getting 50-60M/s

# reset once you are done
echo 10000 > /proc/sys/dev/raid/speed_limit_min
echo 1024 > /sys/block/md2/md/stripe_cache_size