Increase stripe_cache_size for mdadm/md devices permanently

Create /etc/udev/rules.d/60-md-stripe-cache.rules

SUBSYSTEM=="block", KERNEL=="md*", ACTION=="change", TEST=="md/stripe_cache_size", ATTR{md/stripe_cache_size}="16384"

Reload udev rules, will take effect immediately.

udevadm control --reload-rules

udevadm trigger

Confirm (where md0 is your md device in question)

cat /sys/devices/virtual/block/md0/md/stripe_cache_size