dd and smart monitoring tool hangs when disk is unmapped.

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.

Out of curiosity, could you help me understand what you mean by
“unmapped”? How is this disk connected to the system (physically, SAN,
iSCSI, MPIO, etc.)?

Also, do you have the ‘dd’ command in use? I’ve used dd against disks in
the past and I usually try to check to see the disk is there first because
of the time ‘dd’ takes to read in the whole “file” (disk) otherwise.

Good luck.

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