We are using SLES 12 SP1 on Power8 servers.
In a case f ours, we are trying to monitor a storage disk (ds8k) using dd and smart monitoring tool.
As part of this case we need this monitoring when disk is unmapped, but in this case dd and smart monitoring hangs with no warning - no error (waited more than 10 mins).
dd in this same scenario on other Linux flavors is working fine.
Please help, and do let let us know what all logs or information you need to help.