Hello Andy
It just looks like a dying disk to me or a bad cable. Better get off the data quickly. Why do you think it's related to the barriers?
The disks in question are brand new and two times exchanged Google References re the entries below pointed to write through cache / barrier problems if the hint you gave was not the most probable reason ... Mar 2 18:29:50 celsius01 kernel: hdi: drive_cmd: status=0x51 { DriveReady +SeekComplete Error }
Mar 2 18:29:50 celsius01 kernel: hdi: drive_cmd: error=0x04 { +DriveStatusError } Mar 2 18:29:51 celsius01 [powersave_proxy][7632]: WARNING: hdparm returned +error 5 Mar 2 18:29:51 celsius01 kernel: hdk: drive_cmd: status=0x51 { DriveReady +SeekComplete Error } Mar 2 18:29:51 celsius01 kernel: hdk: drive_cmd: error=0x04 { +DriveStatusError }
TIA Micha