Consistent mismatch count on a kernel RAID1

Question

I've got two partitions in a RAID1.  cat'ing the mismatch_cnt for this (the only) array is now producing 122 consistently.  I've tried:
- echo'ing repair and check into sync_action for this array many times.  A cron job used to do each once on different nights of the week, now it's doing repair nightly
- running smartctl --test long on both of the HDs that have these partitions
- starting the system from SystemRescueCD and doing fsck.ext4 -fvvck
I don't know how to see any results from the repair/check actions.  The SMART test results indicate no problems on either physical HD.  The filesystem check produced no errors.  Does anyone have any other suggestions as to what I might to do fix this?  This is my root partition, not a swap and there's no swap file on this filesystem.  After a reboot the mismatch is 0 until I do a check or repair, then it's 122.  The system is an up-to-date 64-bit Arch installation, the filesystem is ext4 mounted with defaults.  Thanks.

Answer 1

Updated my Chromebook to systemd - no problems at all. Just swapped out init=/sbin/init for init=/usr/lib/systemd/systemd
This can be done post-install, under ChromeOS, by redownloading make_dev_ssd.sh and common_minimal.sh, remounting /tmp as exec and copying those shell scripts there, and then running (in /tmp):
sudo ./make_dev_ssd.sh --partitions '6' --save_config arch
sudo vim arch.6 # change init=
sudo ./make_dev_ssd.sh --partitions '6' --set_config arch
Obviously this also applies to changing any other kernel parameters.
As a sidenote, I use both Arch and CrOS regularly. I use CrOS as the "default" OS, and I have:
alias archboot = 'sudo cgpt add -i 6 -T 1 -P 5 -S 0 /dev/sda && sudo reboot'
in my user's ~/.bash_profile so that when I'm logged in to CrOS, Arch is just a Ctrl-Shift-T (opens crosh), "shell" (opens bash), "archboot" and then my root password away. Both Arch and CrOS have very minimal bootup times, so this serves me well.
Obviously hitting Ctrl-D on every boot to clear the Sad Chromebook is a bit annoying, but not too bad. The beep still surprises me sometimes if I forget!