99.99 % [jbd2/drbd0-8] highiowait -
99.99 % [jbd2/drbd0-8] highiowait
I have not found the source of this but essentially it seems like drbd and ext4 may not play well but I have to confirm still.
In either case an older DRBD setup with older hard drives seems to have little to no iowait, but the main difference is the drbd partition is ext3 and not ext4. I will experiment and see if that fixes this, then we will know that DRBD and ext4 have issues.