I did a little research and saw an article that specifically had this error in it. It indicated:
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NOTE: if the message “Hardware specific failure: failed to
unconfigure SCSI device: I/O error” appears, check to make sure that you cleared all replicas and metadevices from the disk, and that the disk is not being accessed
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I didn't want to remove all the replicas, etc, since I was just testing. Do you think this is why I couldn't cfgadm? I actually tested by doing an init 0 and reboot (which booted to the second drive, then issue a metareplace for all devices. They seem to be resyncing.
Would the cfgadm -f -s unconfigure worked instead of just the cfgadm -c unconfigure?
Thanks