I would highly recommend to set snaphot_autoextend_threshold and
thin_pool_autoextend_threshold to 70 (or another reasonable value)
by default than disabling the autoextend feature. AFAICT the dmeventd
infrastructure is in place, anyway.

Without autoextend a snapshot exceeding its limits is fatal. The
default warnings dmeventd writes to syslog are easy to miss.


Regards

Harri