Now using:
4.8.0-49-generic #52-Ubuntu SMP Thu Apr 20 09:38:39 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
related to heavy disc load, typically an rsync running as part of backup. But the sda drive is the only one that generates the errors, sdb and sdc that actually have the backup files don't give errors.
Now using:
4.8.0-49-generic #52-Ubuntu SMP Thu Apr 20 09:38:39 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
related to heavy disc load, typically an rsync running as part of backup. But the sda drive is the only one that generates the errors, sdb and sdc that actually have the backup files don't give errors.